mccfrank:

I have the exact same problem and noticed your post shortly after posting mine here: https://support.mozilla.org/en-US/questions/1340621

Have you found a solution?

No, no answers yet. I suspect it's a bug introduced in the latest version 78 which in my case updated late yesterday. I have filed a bug and apparently it's being worked on.

I have filed a bug with Mozilla

Have you got a bug ID?

I have not filed a bug yet. I can verify that if I create the account from a fresh installation of TB on a VM, that I receive the Gmail popup requesting my credentials and prompting me to grant Thunderbird access permissions, and then everything works fine. Same account, same credentials, same LAN, same version of TB. I've closed TB down on the VM, launched it again and it works like normal.

But my older version of TB, recently upgraded via 'apt upgrade', continues to give the same error message.

I think we just need to find the way to force TB to prompt Gmail with the login window and grant permission screen... I just haven't figured out how to do this without deleting the account and adding it again. I've got hundreds of filters and do not want to go through that again...

Bug number 1716320

I downloaded the latest Thunderbird from Mozillas site and installed it in my home directory. It works flawlessly. So it's the Apt upgrade version which has the problem.

mccfrank - christ1 believes this is related to Debian update issue. Are you running Debian?

psilospiral: Yes Debian Bullseye.

It is related to Debian. It only started after this morning updates.

mccfrank - also, I can install this from Debian repos with 'apt install thunderbird' on a VM, enter my credentials, and it works as expected on 78.11.0. This should be the exact same thing I end up with when doing an 'apt update && apt upgrade -y' , yet my upgraded version is presenting NS_ERROR_NET_INADEQUATE_SECURITY after the upgrade.

The only hint that is different is that after the upgrade, I was never presented with a Gmail popup asking to re-authenticate and grant TB access permissions, while this was done when adding a new account to a fresh installation. I feel like this is related to the issue.

mccfrank - I am also running Debian 11. I have a Proxmox VM running TB 78.10.0 and it was working fine. I ran a quick vzdump backup, ran an apt update && apt upgrade -y, which took TB from 78.10.0 to 78.11.0, and now I am getting the exact same error on that VM as well. I just restored from the backup, dropping TB back to 78.10.0, and I'm back to working again as before.

A fresh installation of 78.11.0 from the Debian repos works fine though when setting up a new account. I'm just trying to avoid deleting the gmail account and re-adding it....

Matt over here: https://support.mozilla.org/en-US/questions/1340653 provided a link that solved my issue. Give this a shot:

Click the three horizontal bars to display the main menu in upper right hand corner Preferences>Config Editor (either scroll down or type "config editor" in the search bar) Click "I accept the risk" Type into the search bar: network.http.spdy.enabled.http2 Double-click the entry to toggle from true to false

Gmail is working again!

psilospiral: That's great it worked for me as well. As soon as I toggled it gmail connected properly. Now I wonder what that preference is and what else it may affect.

Well for now for me at least and for a few others the problem is solved.

Thanks for passing that on!

Yes sir - glad I could help! I also do not know why this had to be toggled after an 'apt update && apt upgrade', but this is certainly going in my TB notes.

I can confirm that my VM with TB 78.10.0 has the tunable 'network.http.spdy.enabled.http2' set to TRUE. Immediately following an 'apt update && apt upgrade', the same tunable is still TRUE. So, the upgrade does not toggle this setting.