Using thunderbird 115.2.0(64bit)

State the antivirus, VPN (if used), especially if it is not Windows Security, e.g. Avast, AVG etc.

Antivirus is mcafee; no vpn enabled. Its a very simple setup

McAfee might be (probably is) the cause. Try disabling any option in McAfee that scans the TB profile folder or scans secure connections. The best way to test its effect is to run Windows in safe mode, then see if sending works.

McAfee might be (probably is) the cause. Try disabling any option in McAfee that scans the TB profile folder or scans secure connections. The best way to test its effect is to run Windows in safe mode, then see if sending works.

Thankyou for the suggestion, I have uninstalled Mcafee and restarted in safe mode with networking. There is no change in behaviour :(. sending via smtp still timesout

There have been changes in oauth in Thunderbird and Microsoft's implementation of acceptable authentication methods in recent times.

I suggest you create a new profile in Thunderbird and set up one of your accounts there and try and send using that. If it works then the Thunderbird authentication changes are the issue and "can" be fixed by a lot of fiddling in the config editor but if at all possible just add all your accounts to the new profile as the things to be deleted are rather simple and at the same time complex to determine. A bit like some of the windows register changes that can be manually implemented.

There have been changes in oauth in Thunderbird and Microsoft's implementation of acceptable authentication methods in recent times. I suggest you create a new profile in Thunderbird and set up one of your accounts there and try and send using that. If it works then the Thunderbird authentication changes are the issue and "can" be fixed by a lot of fiddling in the config editor but if at all possible just add all your accounts to the new profile as the things to be deleted are rather simple and at the same time complex to determine. A bit like some of the windows register changes that can be manually implemented.

Very painful process, but it worked. Uninstalled Thunderbird, Deleted all thunderbird folders in appdata/local and appdata/roaming. reinstalled thunderbird, then added each account with the same settings again. They are all working except the uni one, but that may be a uni problem now :). Thankyou for your help

Matt said

There have been changes in oauth in Thunderbird and Microsoft's implementation of acceptable authentication methods in recent times. I suggest you create a new profile in Thunderbird and set up one of your accounts there and try and send using that. If it works then the Thunderbird authentication changes are the issue and "can" be fixed by a lot of fiddling in the config editor but if at all possible just add all your accounts to the new profile as the things to be deleted are rather simple and at the same time complex to determine. A bit like some of the windows register changes that can be manually implemented.

Very painful process, but it worked. Uninstalled Thunderbird, Deleted all thunderbird folders in appdata/local and appdata/roaming. reinstalled thunderbird, then added each account with the same settings again. They are all working except the uni one, but that may be a uni problem now :). Thankyou for your help

It got there, but creating is new profile to use is much simpler. You just go to the about:profiles in the troubleshooting information on the help menu and create one. No uninstalling removing or any of it.