Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

error codes

  • 4 replies
  • 1 has this problem
  • Last reply by cor-el

more options

i am getting the following error message. The websites work on other browsers. I have cleared data and history and removed AVG free anti virus. Firefox just will not connect. i am a novice so any help would be appreciated.

Secure Connection Failed

An error occurred during a connection to A required TLS feature is missing. Error code: MOZILLA_PKIX_ERROR_REQUIRED_TLS_FEATURE_MISSING

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.

Learn more…

Report errors like this to help Mozilla identify and block malicious sites

All Replies (4)

more options

I tried one of the links and I got;

Category: Intrusion Prevention Date & Time,Risk,Activity,Status,Recommended Action,IPS Alert Name,Default Action,Action Taken,Attacking Computer,Destination Address,Source Address,Traffic Description

6/6/2019 7:55:36 AM,Medium,An intrusion attempt by was blocked.,Blocked,No Action Required,Malicious Site: Malicious Domain Request 22,No Action Required,No Action Required," (, 443)","FRED-PC (, 56968)", (,"TCP, https"

Network traffic from matches the signature of a known attack. The attack was resulted from \DEVICE\HARDDISKVOLUME3\PROGRAM FILES\MOZILLA FIREFOX 54\FIREFOX.EXE. To stop being notified for this type of traffic, in the Actions panel, click Stop Notifying Me.

more options

Hi Fred

Thank you so much for taking the time to look at this. I have a follow up question on this matter given your response.

Does this mean that my computer is infected and if it is how do I find and remove problem?

Your help is very much appreciated as I am not sure what to do.

Many thanks

more options

tiger108 said

Does this mean that my computer is infected

I don't know. Further information can be found in this article;

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

more options

This could be a problem with OCSP stapling.

Try to disable OCSP Stapling temporarily by toggling this pref to false on the about:config page to see if that has effect.

  • security.ssl.enable_ocsp_stapling = false

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

It is best to reset this pref via the right-click context menu to true once you are done with accessing an affected website since this is a security feature.

See also: