Hi Thunderbird needs to know the same password you would use if you were accessing your email online (e.g. Gmail, Yahoo, Verizon...). So, for example if your password was changed in Gmail, or you set up two stage authentication, Thunderbird would need to be updated to use the same new password. Is that what happened? Are you still able to get to your email through your online account? If you can, then you need to update Thunderbird's password. If you uninstalled Thunderbird, the process to reconnect with your old profile is different. Please explain more about what happened to cause this. Thanks and good luck. Agnes

Hello, Agnes, thank you very much for your answer. (Excuse me, my english is not very good.) I can indeed access my e-mails via my Free account, but I can not send any more via Thunderbird (which I uninstalled and reinstalled recently, to no avail). I get this message: "The message could not be sent because the SMTP connection" smtp.free.fr "has expired, please try again." Thanks again !

Perhaps some settings were lost when you uninstalled and reinstalled. The settings that allow communication with your email servers need to be reset. Your best option is to talk to free.fr support and get them to tell you the SMTP settings to enter in Thunderbird. There is some troubleshooting help here: https://support.mozilla.org/en-US/kb/cannot-send-messages - look at the SMTP settings parts and try https://www.free.fr/assistance/2406.html for the settings you should have in there. Good luck! Agnes

I uninstalled and reinstalled Thunderbird only after my problems started. But I will try what you suggest. Thank you so much. Dib.

Dibonjour said

I uninstalled and reinstalled Thunderbird only after my problems started. But I will try what you suggest. Thank you so much. Dib.

This is usually a good way to make a problem worse. Deleting the account in Thunderbird and adding it again is also non productive but often results in data loss.