Firefox Community Forum

To be honest. Firefox is starting to be a big pain to use. I'm starting to see more and more of this screen where it say's "Be careful. Something doesn't look right" Even when i go to the advance and say proceed. Nothing happens and i'm getting no where. I know many of the sites don't have anything to do with asking for credit card, Scam or even having popup's. I test the sites in other browsers and there work without any issues. But Firefox is starting to lock me out of many sites due to this. How can i make this stop. As i used Firefox for many years.

The sample that is in the screenshot is a Anime data base that i have also used for years. But today shows this. But was working fine yesteday. What is going on and how can i fix it. So i can start using the browser that i love on the sites i want to.

I have started receiving a secure connection failed error message for a portal log-in website that worked fine for the past 6-7 months (see attached document). Other people in my group use Firefox and Bitdefender to access the portal and none of them are having this issue.

I originally believed the problem to be my anti-virus (Bitdefender) and worked with them to resolve the problems. After trying various solutions including clearing my cache, using private mode and turning off different components of their software, Bitdefender believes the problem is with my browser setting and not their software. I also tried accessing the portal using Chrome in both regular and incognito modes and cannot access the site which would seem to rule out the problem being a Firefox browser problem but contacting Firefox support seems to be the next logical step.

I have been to the Firefox FAQ and saw similar problems with potential solutions - DNS over HTTPS, TLSKEYLOGGING issues, add-on exceptions - none of which worked. I have the most recent version of Firefox and am running Windows 11 home version.

Sometimes if I hit refresh after receiving the error message, the browser will try to connect and I will get a server time out message. If I keep hitting "try again", sometimes the portal log-in screen will appear and allow me to log-in. The key word is "sometimes" since often I just keep getting the server time out message.

Any ideas for me to try from this forum?

I just installed Firefox on my PC haven't had it on this computer since reinstalling windows - I imported my bookmarks and passwords from Edge, thinking it would be a seamless transition, since I used Firefox in the past without much trouble.

Two weeks on, about 95% of every page I open gives an error similar to the one below, and I have to shift+refresh several times to get it to reload before it goes away, (some sites still don't open).

I wonder how common this issue is, and how people fixed it?

Be careful. Something doesn't look right.

Firefox spotted a potentially serious security issue with connect.mozilla.org. Someone pretending to be the site could try to steal things like credit card info, passwords, or emails.

Go back (Recommended)

Hide advanced

Advanced What makes the site look dangerous? The site is set up to allow only secure connections, but there's a problem with the site's certificate. It's possible that a bad actor is trying to impersonate the site. Sites use certificates issued by a certificate authority to prove they're really who they say they are. Firefox doesn't trust this site because its certificate isn't valid for connect.mozilla.org. The certificate is only valid for: *. eero.com. What can you do about it? Probably nothing, since it's likely there's a problem with the site itself. Sites use certificates issued by a certificate authority to prove they're really who they say they are. But if you're on a corporate network, your support team may have more info. If you're using antivirus software, try searching for potential conflicts or known issues. View the site's certificate Learn more about secure connection failures Error Code: SSL_ERROR_BAD_CERT_DOMAIN Jun 5, 2026 10:58:34 AM GMT+10

Proceed to connect.mozilla.org (Risky)

Hello, I am facing a very strange and frustrating issue with my website https://biografieblick.de/, and it is only happening on the firefox browser other browsers like chrome, edge or safari are loading the site perfectly fine. The Issue is it occurs occasionally, Yeahh IDK why. When I try to visit my site, Firefox gets stuck on a screen that says "Checking if the site connection is secure" and it looks like an loop sometimes.

This looks exactly like a cloudflare turnstile loop but I am NOT using cloudflare. I have double checked my DNS records and explicitly confirmed this with my web hosting provider. This block only triggers when using firefox.

An error occurred during a connection to ezproxy.yu.edu.jo. PR_CONNECT_RESET_ERROR

Error code: PR_CONNECT_RESET_ERROR

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the website owners to inform them of this problem.

Learn more…

I am able to open all these sites in Edge and Chrome. Firefox is not allowing me to open any website including https://support.mozilla.org/1/firefox/141.0.3/WINNT/en-US/firefox-help

Here is one for www.theepochtimes.com Firefox blocked your visit to this site because the signature on the certificate provided for linkprotect.cudasvc.com isn’t valid.

Error code: SEC_ERROR_BAD_SIGNATURE

View Certificate

https://linkprotect.cudasvc.com/url?a=https%3a%2f%2flists.theepochtimes.com%2flinks%2fdYekYfa9b%2fHhryKHE6n%2fm46Mv1lM35xm%2ffPxqlcxbEy&c=E,1,ZCIg6L-Y-rIKvrOC91Rng41YHEp3yXHnFOrkZ-dEbsu8eJmVYw5eygLlFsHlgdf1Tmry7UZgvuCl6QoNJHES1kUyjNFgc3z8J5-hU70LqRt8blmn&typo=1

Peer’s certificate has an invalid signature.

HTTP Strict Transport Security: false HTTP Public Key Pinning: false

Certificate chain:

MIIB3TCCAYKgAwIBAgIIOvW4RpHf51AwCgYIKoZIzj0EAwIwTTELMAkGA1UEBhMC TFQxFTATBgNVBAoMDE5vcmRWUE4gUy5BLjEnMCUGA1UEAwweTm9yZFZQTiBTLkEu IC1UaHJlYXRQcm90ZWN0aW9uMB4XDTI1MDgyNTE5MTA1NFoXDTI2MDgyNTE5MTU1 NFowJDEiMCAGA1UEAwwZKi5saW5rcHJvdGVjdC5jdWRhc3ZjLmNvbTBZMBMGByqG SM49AgEGCCqGSM49AwEHA0IABGrx92NDDePfCVmGrn4StYMr6XU2mdhqpiE51CmT XEnX6cYCaE1KyVrw09JFubcGZSmUUllYqKjKop6A4uds/5SjdTBzMB0GA1UdDgQW BBTUcdvR66YYJKl/X5qqiMfeJn5XtjATBgNVHSUEDDAKBggrBgEFBQcDATA9BgNV HREENjA0ghkqLmxpbmtwcm90ZWN0LmN1ZGFzdmMuY29tghdsaW5rcHJvdGVjdC5j dWRhc3ZjLmNvbTAKBggqhkjOPQQDAgNJADBGAiEA2a31LBw2Ab2UixVdpVQpJwx0 hW5mLG/KCvuyrACqUQ8CIQDAnirOaJT0OuV3d4jeznV7DaLdY7RqVDXyuGNZwXDZ Fw==

I'm using firefox in my company's intranet, it needn't to check whether the website is secure or not. So this warning is so annoying.

I want to turn it off, but how? The instructions I searched on the Internet are out of date.

The browser version is 137.0

i can't do a search. I keep getting "problem loading page" and "secured connection failed" This is happening on both my windows 7 computer and my windows 10 computer. The same thing is happening if I try a google search as well.

Untill last night i could conect with that site https://imtw.ru and its sub forums without eny problem . Today when i press the link i recieve a message that the connection is rejected "Failure to secure connection". As you van see it has the https:// infront and i repeat i was able to connect last night. What may be wrong?

I have a home server 192.168.0.240 in my local network. Firefox does not let me in to my own pages. On the address line appears text "Not secure",

I have found no way to get in. I have there REALLY IMPORTANT TOOLS AND MATERIAL and I need it AS SOON AS POSSIBLE !!!!

This is really stupid. I have used these pages until this weekend. I have had this problem many years, but always found some way to make it work. I am NOT going to buy a certificate to every server I have home. it costs $$$$.

Why are you closing the baked-in cert expiration support thread two days before it happens? Wouldn't it make a whole ton more sense to leave it open during the actual problem period?

https://support.mozilla.org/en-US/questions/1468274

Site: https://www.thegamer.com Firefox refuses to load the site, it does not even show the certificate when clicking on the lock. Using the certificate manager, add exception does not work too, it just refuses to store the certificate. But at least THERE I can VIEW the certificate, which proves it is valid and FIREFOX is at fault:

https://www.ssllabs.com/ssltest/analyze.html?d=www.thegamer.com&latest shows "IO exception" when trying to check the CRL, but gives an A+. Yet Firefox does not even give me the "Continue anyway" possibility. This it tiering, I hate using google chrome based browsers, but of course, it works there. Server 2025, only MS-defender at its default settings.

Subject Name Common Name thegamer.com Issuer Name Country US Organization Let's Encrypt Common Name E8 Validity Not Before Mon, 13 Oct 2025 23:03:42 GMT Not After Sun, 11 Jan 2026 23:03:41 GMT Subject Alt Names DNS Name

• .thegamer.com

DNS Name thegamer.com Public Key Info Algorithm Elliptic Curve Key Size 256 Public Value 04:0E:95:16:C4:A2:23:9D:81:AD:D7:70:4C:4B:A5:F7:68:0E:33:E2:A0:1C:81:6D:0F:1C:F5:C8:EF:5B:C8:64:AD:15:86:5D:5E:E6:FA:A6:DB:41:86:A5:F0:28:7A:45:F4:8D:75:B3:18:43:E9:0F:7C:75:10:AE:F8:A0:04:7B:D5 Miscellaneous Serial Number 06:6C:A7:00:7C:ED:C0:50:E2:FD:4F:6C:A0:8C:0F:86:2B:AD Signature Algorithm ECDSA with SHA-384 Version 3 Download PEM (cert)PEM (chain) Fingerprints SHA-256 D0:D5:E8:73:9E:6D:B1:2D:EC:5D:47:0D:70:BF:58:1C:AC:A5:D3:89:20:6D:54:15:09:E8:42:9C:82:F7:4F:8F SHA-1 53:E6:54:B5:37:0F:4B:23:BE:73:8A:6B:37:6B:BE:A6:A5:86:E4:5B [This extension has been marked as critical, meaning that clients must reject the certificate if they do not understand it.] Basic Constraints Certificate Authority No [This extension has been marked as critical, meaning that clients must reject the certificate if they do not understand it.] Key Usages Purposes Digital Signature Extended Key Usages Purposes Server Authentication, Client Authentication Subject Key ID Key ID 53:6A:02:33:30:1C:AD:4D:3B:F2:9F:4D:6D:E4:33:26:31:69:8F:61 Authority Key ID Key ID 8F:0D:13:A2:F6:2E:7E:D1:50:6C:33:18:38:5D:59:8E:23:72:91:CA CRL Endpoints Distribution Point http://e8.c.lencr.org/46.crl Authority Info (AIA) Location http://e8.i.lencr.org/ Method CA Issuers Certificate Policies Policy Certificate Type ( 2.23.140.1.2.1 ) Value Domain Validation Embedded SCTs Log ID 0E:57:94:BC:F3:AE:A9:3E:33:1B:2C:99:07:B3:F7:90:DF:9B:C2:3D:71:32:25:DD:21:A9:25:AC:61:C5:4E:21 Signature Algorithm SHA-256 ECDSA Version 1 Timestamp Tue, 14 Oct 2025 00:02:12 GMT Log ID 19:86:D4:C7:28:AA:6F:FE:BA:03:6F:78:2A:4D:01:91:AA:CE:2D:72:31:0F:AE:CE:5D:70:41:2D:25:4C:C7:D4 Signature Algorithm SHA-256 ECDSA Version 1 Timestamp Tue, 14 Oct 2025 00:02:12 GMT

Subject Name Country US Organization Let's Encrypt Common Name E8 Issuer Name Country US Organization Internet Security Research Group Common Name ISRG Root X1 Validity Not Before Wed, 13 Mar 2024 00:00:00 GMT Not After Fri, 12 Mar 2027 23:59:59 GMT Public Key Info Algorithm Elliptic Curve Key Size 384 Public Value 04:D1:65:F2:5E:DC:4B:B4:0C:02:9C:D2:B2:FA:EE:E9:6C:AB:3A:AE:38:A1:F4:D4:39:32:33:C5:42:D4:CC:33:0C:34:C7:21:20:90:70:5C:E8:62:2F:1C:71:B3:42:D7:79:BE:46:0D:C1:DB:47:A1:13:A0:C7:DF:81:26:63:3B:D4:8D:1D:F6:3D:82:33:32:F6:F4:2B:E7:F5:96:3A:B4:13:67:18:7B:6B:3E:8D:48:D9:EA:DE:ED:AE:6D:3E:87:4C Miscellaneous Serial Number 63:95:93:63:C2:4E:70:82:71:59:18:BF:C3:D7:ED:56 Signature Algorithm SHA-256 with RSA Encryption Version 3 Download PEM (cert)PEM (chain) Fingerprints SHA-256 83:62:4F:D3:38:C8:D9:B0:23:C1:8A:67:CB:7A:9C:05:19:DA:43:D1:17:75:B4:C6:CB:DA:D4:5C:3D:99:7C:52 SHA-1 54:31:7E:B0:76:5F:0B:C6:74:85:51:84:EB:83:74:B4:19:9E:46:55 [This extension has been marked as critical, meaning that clients must reject the certificate if they do not understand it.] Basic Constraints Certificate Authority Yes [This extension has been marked as critical, meaning that clients must reject the certificate if they do not understand it.] Key Usages Purposes Digital Signature, Certificate Signing, CRL Signing Extended Key Usages Purposes Client Authentication, Server Authentication Subject Key ID Key ID 8F:0D:13:A2:F6:2E:7E:D1:50:6C:33:18:38:5D:59:8E:23:72:91:CA Authority Key ID Key ID 79:B4:59:E6:7B:B6:E5:E4:01:73:80:08:88:C8:1A:58:F6:E9:9B:6E CRL Endpoints Distribution Point http://x1.c.lencr.org/ Authority Info (AIA) Location http://x1.i.lencr.org/ Method CA Issuers Certificate Policies Policy Certificate Type ( 2.23.140.1.2.1 ) Value Domain Validation

Subject Name Country US Organization Internet Security Research Group Common Name ISRG Root X1 Issuer Name Country US Organization Internet Security Research Group Common Name ISRG Root X1 Validity Not Before Thu, 04 Jun 2015 11:04:38 GMT Not After Mon, 04 Jun 2035 11:04:38 GMT Public Key Info Algorithm RSA Key Size 4096 Exponent 65537 Modulus AD:E8:24:73:F4:14:37:F3:9B:9E:2B:57:28:1C:87:BE:DC:B7:DF:38:90:8C:6E:3C:E6:57:A0:78:F7:75:C2:A2:FE:F5:6A:6E:F6:00:4F:28:DB:DE:68:86:6C:44:93:B6:B1:63:FD:14:12:6B:BF:1F:D2:EA:31:9B:21:7E:D1:33:3C:BA:48:F5:DD:79:DF:B3:B8:FF:12:F1:21:9A:4B:C1:8A:86:71:69:4A:66:66:6C:8F:7E:3C:70:BF:AD:29:22:06:F3:E4:C0:E6:80:AE:E2:4B:8F:B7:99:7E:94:03:9F:D3:47:97:7C:99:48:23:53:E8:38:AE:4F:0A:6F:83:2E:D1:49:57:8C:80:74:B6:DA:2F:D0:38:8D:7B:03:70:21:1B:75:F2:30:3C:FA:8F:AE:DD:DA:63:AB:EB:16:4F:C2:8E:11:4B:7E:CF:0B:E8:FF:B5:77:2E:F4:B2:7B:4A:E0:4C:12:25:0C:70:8D:03:29:A0:E1:53:24:EC:13:D9:EE:19:BF:10:B3:4A:8C:3F:89:A3:61:51:DE:AC:87:07:94:F4:63:71:EC:2E:E2:6F:5B:98:81:E1:89:5C:34:79:6C:76:EF:3B:90:62:79:E6:DB:A4:9A:2F:26:C5:D0:10:E1:0E:DE:D9:10:8E:16:FB:B7:F7:A8:F7:C7:E5:02:07:98:8F:36:08:95:E7:E2:37:96:0D:36:75:9E:FB:0E:72:B1:1D:9B:BC:03:F9:49:05:D8:81:DD:05:B4:2A:D6:41:E9:AC:01:76:95:0A:0F:D8:DF:D5:BD:12:1F:35:2F:28:17:6C:D2:98:C1:A8:09:64:77:6E:47:37:BA:CE:AC:59:5E:68:9D:7F:72:D6:89:C5:06:41:29:3E:59:3E:DD:26:F5:24:C9:11:A7:5A:A3:4C:40:1F:46:A1:99:B5:A7:3A:51:6E:86:3B:9E:7D:72:A7:12:05:78:59:ED:3E:51:78:15:0B:03:8F:8D:D0:2F:05:B2:3E:7B:4A:1C:4B:73:05:12:FC:C6:EA:E0:50:13:7C:43:93:74:B3:CA:74:E7:8E:1F:01:08:D0:30:D4:5B:71:36:B4:07:BA:C1:30:30:5C:48:B7:82:3B:98:A6:7D:60:8A:A2:A3:29:82:CC:BA:BD:83:04:1B:A2:83:03:41:A1:D6:05:F1:1B:C2:B6:F0:A8:7C:86:3B:46:A8:48:2A:88:DC:76:9A:76:BF:1F:6A:A5:3D:19:8F:EB:38:F3:64:DE:C8:2B:0D:0A:28:FF:F7:DB:E2:15:42:D4:22:D0:27:5D:E1:79:FE:18:E7:70:88:AD:4E:E6:D9:8B:3A:C6:DD:27:51:6E:FF:BC:64:F5:33:43:4F Miscellaneous Serial Number 00:82:10:CF:B0:D2:40:E3:59:44:63:E0:BB:63:82:8B:00 Signature Algorithm SHA-256 with RSA Encryption Version 3 Download PEM (cert)PEM (chain) Fingerprints SHA-256 96:BC:EC:06:26:49:76:F3:74:60:77:9A:CF:28:C5:A7:CF:E8:A3:C0:AA:E1:1A:8F:FC:EE:05:C0:BD:DF:08:C6 SHA-1 CA:BD:2A:79:A1:07:6A:31:F2:1D:25:36:35:CB:03:9D:43:29:A5:E8 [This extension has been marked as critical, meaning that clients must reject the certificate if they do not understand it.] Basic Constraints Certificate Authority Yes [This extension has been marked as critical, meaning that clients must reject the certificate if they do not understand it.] Key Usages Purposes Certificate Signing, CRL Signing Subject Key ID Key ID 79:B4:59:E6:7B:B6:E5:E4:01:73:80:08:88:C8:1A:58:F6:E9:9B:6E

An error occurred during a connection to in.pinterest.com. PR_CONNECT_RESET_ERROR

Error code: PR_CONNECT_RESET_ERROR

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the web site owners to inform them of this problem.

Clear Error code: PR_END_OF_FILE_ERROR This is only on Amazon.com. Secure Connection Failed

An error occurred during a connection to www.amazon.com. PR_END_OF_FILE_ERROR

Error code: PR_END_OF_FILE_ERROR

   The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
   Please contact the website owners to inform them of this problem.

Learn more…