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How do I fix this Sending of message failed.

An error occurred while sending mail. Th mail server responded Policy -MFRM53 Relay Denied-unauthoruzed. Please verify that your email address is correct in your account settings and try again

What should I do

I upgraded my 2012 macbook pro to the latest version of thunderbird and I can not get my emails. I am running os10.15.8 Every time I try to get messages a yahoo page opens up and wants me to sign into my yahoo account. I can't get rid of the yahoo page it just keeps reopening again and again. Everything was working fine until I upgraded thunderbird to 153.0.3esr. My other mac that has not been upgraded can still get my emails.

Is it possible to go back to the prior versions of thunderbird or make this new version work with my mac?

I have had sky email for too many years to count. I have always used Mozilla Thunderbird for my emails on my laptop so that I can do essential housekeeping to manage my emails in to logical folders.

I won't bore you with the details but this week I have had an issue that resulted in deleting the 16 digit code. When I go through to the link

https://www.sky.com/sky-yahoo-mail/manage-apps

I get the following error message:

Sorry, something seems to have gone wrong. Please check your connection and try again later.

I have received this error message for the last week. I am going round in circles.

Can anyone help me to access my emails on Thunderbird?

Thunderbird version: 153.0.3 (64-bit), Meadow, release channel, fully up to date.

I can successfully insert my local PNG into a composed HTML email, tick “Attach this image to the message,” and add a hyperlink to the image. The hyperlink works when the email is sent.

The problem occurs when trying to use this permanently as the account signature. HTML signatures I've tried either lose the image, show a broken-image icon, or fail to preserve the clickable image when used automatically.

I have also tested an HTML signature using a local file:///C:/... image reference, which produces a broken-image icon in Thunderbird.

I do not want to host the image remotely. I want the PNG embedded in the HTML/signature and sent with each email.

Can you confirm the correct method specifically for Thunderbird 153.0.3 on Windows, and whether there is a current issue with embedded/Base64 images or clickable image signatures in this version?

One of the e-mails account receive mails verry slow for a few days. The other 2 works perfect. I have tryde all the sollutions I could find on internet, but I have still the problem

I am using Thunderbird Meadow.

Is it possible to send emails without a subject, other than getting the warning dialogue box.

It would be very useful.

Thank you

Thunderbird downloads new emails for all my emails except one. Has not downloaded on that one since July 3. Have reset various background settings to match other email accounts. Running on Windows 10. Suggestions?

Using the same settings as my main account: imap.gmail.com SSL/TLS 0Auth2 Tried copying in same local directory as one that is working. No idea what all these do...

I have used Thunderbird for years with complete success. Recently (within the past month) I have lost the ability to send (SMTP) mail and receive the following error message: "Send Message Error, Sending of the message failed. Unable to authenticate to Outgoing server (SMTP). Please check the password and verify the 'Authentication method' in 'Account Settings | Outgoing server (SMTP)." [I just change my from address to another one going through Network Solutions and the mail sends just fine.]

Everything seems to be in order when checking my settings. I finally called Yahoo and spent an hour on the phone with them, including a supervisor (in the background) and they were unable to correct the situation. Yes, since I had called them from their tech support line (I looked it up; did not call anything sent to me) and they worked on my computer trying to fix it. They finally said it was a Thunderbird issue and said I needed to contact Thunderbird.

I am able to send from my phone (Android) using the same cox.net e-mail address. My wife is able to send from her computer using her cox.net via Thunderbird. My wife's incoming mail is IMAP while mine are all POP.

I happen to have several cox.net accounts and get the same SMTP error on all. However, all receive POP mail just fine, but see the next paragraph.

[As an aside (?), I should note that after Yahoo attempted to "fix" the problem, ALL my incoming cox.net mail comes into ALL of my cox.net accounts regardless of which one is addressed.]

I don't even know where to start at this point. Thanks for any help.

Bill

For a few weeks now, sent emails have not been appearing in the "Sent" folder. The recipient receives the email, but I have no confirmation in "Sent" that it was actually sent. It was never a problem.

Attached is a picture of what my account settings looks like. Thunderbird stopped syncing my emails from a gmail account. How do I get it to continue syncing my emails?

Sans aucune raison ni manipulation je n'ai plus de mails dans Thunderbird

J'ai quitté l'application, redémarré mon MacBook et rien n'y change. Quand je vais sur le webmail j'ai bien la totalité de mes mails. Par contre j'avais un dossier local et du coup je n'y ai plus accès non plus

After returning from a 6 day vacation, my wife attempted to download email from her Yahoo email account. There are nearly 200 messages that have piled up but they aren't moving. I've uninstalled and re-installed TB. I've uninstalled and reinstalled the app password in Yahoo. There is no problem with accessing the email via any web browser. I spent 49 minutes on a tech support call with Yahoo and they have said the problem is with TB because they repeated the same steps I have. I checked firewall settings and the only antivirus program on the computer is Malware Bytes and it's not running in the background. The version of TB is the most recent as of yesterday. I don't see any sketchy looking emails in the web version of Yahoo Mail when it's opened. It's set up as a POP3 account and has been since Cox Internet gave their email over to Yahoo. I'd appreciate any assistance in resolving this because it's currently above my pay grade and tech support at Yahoo.

On my iMac, across all thunderbird email accounts, when I click on "New Message", the new window opens up with the Send button and Encrypt button blanked out. To activate the Send button, I have to right click on the Send button, then click on "Customize..." button, then click on "Restore Default Set". Next new message, same drill. This started one day ago and is a pain in the butt. How do I make the Send button live permanently?

I started a monthly donation to Thunderbird a few hours ago and now I'm thinking it may have been a scam. Not sure, and I have sent an email to your donation email about this. Since I made that donation (and maybe this is a coincidence), I am not able to send any emails. I can compose an email, but there is no "send" button anymore. Can you help me with this? Thank you very much.

Bug report 15 Aug. 2026

The disappearing emails.

It took me a while to find out what was going on. My friend said some of his Sent mail was nowhere to be found. After searching for it in a 'wrong' place it does not exist. Sending to the same recipient and again it just disappears. Simplifying the mail down to just address and the word "test", it still disappears. No combination of a Thunderbird search nor an Everything search finds anything. No return error message from this provider nor the recipients.

This address is for the local electricity board, other mails to other departments

go through correctly and are found in the Sent email directory.

A careful inspection of the contact information shows this is the only department

without a "Shown Name" it only has an email address filled in.

Entering a Name for this contact solves the problem, it now shows up in the Sent

folder and is easily searchable.

I hope this explanation helps some one else with a 'Houdini' email.

My Thunderbird email account no longer lets me send out messages. I get a message error

  QUOTE____

Sending of message failed. An error occurred while sending mail. The mail server has responded. Message contains bare CR and is violating 822.bis section 2.3. Please check the message and try again.

But I am able to receive messages.

Can anyone help. Thanks in advance!!