This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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

Cannot send emails after adding on dictionary.

more options

Hi, I installed Thunderbird onto new laptop last week. All working AOK until I added on a dictionary, so that spell check would work. After that, I can receive, but not send emails. I get this message;

  Sending of the message failed.
  Peer's Certificate issuer is not recognised.
  The configuration related to smtp.gmail.com must be corrected.

I checked my account server settings - same as former laptop. Ports etc the same. Question 1 - is installing the dictionary the cause of not being able to send? Question 2 - whatever the cause, what can I do to remedy this?

Please answer simply as I am not a super tech. My understanding of the certificate is its like a handshake between my laptop and other entities. Many thanks, Julie Grace

Hi, I installed Thunderbird onto new laptop last week. All working AOK until I added on a dictionary, so that spell check would work. After that, I can receive, but not send emails. I get this message; Sending of the message failed. Peer's Certificate issuer is not recognised. The configuration related to smtp.gmail.com must be corrected. I checked my account server settings - same as former laptop. Ports etc the same. Question 1 - is installing the dictionary the cause of not being able to send? Question 2 - whatever the cause, what can I do to remedy this? Please answer simply as I am not a super tech. My understanding of the certificate is its like a handshake between my laptop and other entities. Many thanks, Julie Grace

Chosen solution

I suggest you turn off the VPN and see if it makes a difference, as VPNs are obviously designed to mask one's location, and as a result they thwart authentication operations (unless configured to allow them). You might also consider removing AVG, at least temporarily, as such apps are well-known to interfere with email. Removing AVG will mean you revert to the built-in Windows Defender, which has far fewer reports of mail issues.

Read this answer in context 👍 1

All Replies (4)

more options

I doubt the dictionary is the cause of certificate errors, but I suspect you have a security/antivirus app that is scanning outgoing mail and secure connections, and interfering with TB. What is the antivirus? Or, you have a VPN that doesn't allow the usual authentication between TB and gmail.

more options

Thank you. I'm using AVG; have done so for years. When i looked at the VPN tab on this laptop, I could not see much info on it, or even the name of it. On my old laptop, which is still functioning, I can both send and receive emails. The tech guy who set up my new laptop used the server settings as per the old one.

I could ask my tech guy to look at the VPN - can you give any more detail about what we might be looking for? [I don't think it makes any difference, but my old laptop is Toshiba, and this is an Acer Aspire 3.]

Cheers, Julie

more options

Chosen Solution

I suggest you turn off the VPN and see if it makes a difference, as VPNs are obviously designed to mask one's location, and as a result they thwart authentication operations (unless configured to allow them). You might also consider removing AVG, at least temporarily, as such apps are well-known to interfere with email. Removing AVG will mean you revert to the built-in Windows Defender, which has far fewer reports of mail issues.

more options

Hello, I tried a few things like changing port number - nothing. Then got your message, turned VPN off and restarted computer - and could send. Thank you. I read that having no VPN at home is not a drama, but handy when using public WIFI. On a whim I turned the VPN on again - and found I could still send..... I don't quite understand it all, but if it works, it works.

Thank you for taking the time to help me. Thunderbird flies again. Regards, Julie