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IMAP Auththention Method Error

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  • Last reply by k9ykradio

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I'm using Thunderbird 91.8.0 (64-bit) on Win 10. I've not changed any settings on Thunderbird and have suddenly started seeing the following error message pop up: The IMAP server imap.gmail.com does not support the selected authentication method.

The funning thing is that I'm not even using imap.gmail.com. I have my own mail sever set up on my Lan. My mail sever pops email from my gmail account. My settings in thunderbird have my account pointing to my own internal email server, not imap.gmail.com. As I said, I've not changed any settings in Thunderbird, and I've not changed any settings on my personal imap server.

I have Thunderbird 91.5.0 (32-bit) with the exact same IMAP settings running on a different Win 10 machine and it is working fine, so the issue is not on my IMAP server. PLUS, the error message from Thunderbird is report imap.gmail.com. I don't have imap.gmail.com entered in my server settings anywhere, so where is this message coming from?

Thanks for your help!

I'm using Thunderbird 91.8.0 (64-bit) on Win 10. I've not changed any settings on Thunderbird and have suddenly started seeing the following error message pop up: The IMAP server imap.gmail.com does not support the selected authentication method. The funning thing is that I'm not even using imap.gmail.com. I have my own mail sever set up on my Lan. My mail sever pops email from my gmail account. My settings in thunderbird have my account pointing to my own internal email server, not imap.gmail.com. As I said, I've not changed any settings in Thunderbird, and I've not changed any settings on my personal imap server. I have Thunderbird 91.5.0 (32-bit) with the exact same IMAP settings running on a different Win 10 machine and it is working fine, so the issue is not on my IMAP server. PLUS, the error message from Thunderbird is report imap.gmail.com. I don't have imap.gmail.com entered in my server settings anywhere, so where is this message coming from? Thanks for your help!

Chosen solution

I was able to resolve the issue. Your mention of oAuth2.0 was the clue. Looking at Help > more troubleshooting and comparing it to my other computer which was connecting to my imap server just fine I noticed that:

  • On the installation that was having the issue, "authentication method" was changed to OAuth2
  • On the installation that was working fine, "authentication method" was "normal password"

Here's where I think Thunderbird has a BUG ... The installation must have looked at my email address being @gmail.com and assumed that the authentication method needed to change to OAuth2. HOWEVER, while my email address IS @gmail.com, my imap server is my own server, not gmail's. The Thunderbird update process should instead look at the actual imap server address to determine if the auth method should be changed, not the domain of the email address.

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Thanks for your reply Wane, but you must not have really read my post. I’m not connecting to a gmail imap server. I’m connecting to my own imap server running hmail.

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Please post your account details from Help > more troubleshooting

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Seçilmiş Həll

I was able to resolve the issue. Your mention of oAuth2.0 was the clue. Looking at Help > more troubleshooting and comparing it to my other computer which was connecting to my imap server just fine I noticed that:

  • On the installation that was having the issue, "authentication method" was changed to OAuth2
  • On the installation that was working fine, "authentication method" was "normal password"

Here's where I think Thunderbird has a BUG ... The installation must have looked at my email address being @gmail.com and assumed that the authentication method needed to change to OAuth2. HOWEVER, while my email address IS @gmail.com, my imap server is my own server, not gmail's. The Thunderbird update process should instead look at the actual imap server address to determine if the auth method should be changed, not the domain of the email address.