Hi, I hope you can help me please with this issue that popped up today. The email server to which I have been connecting with Thunderbird had a certificate change yesterday. This happens every year and no problem has occurred before. Today with the first send of email with the new certificate Thunderbird warned of the issue and after accepting the certificate exception it successfully sent the email but produced the following error message. "Your message was sent but a copy was not placed in your sent folder (Sent) due to network or file access errors." With option to retry, save (locally) or Don't Save. I tried removing the certificate from Thunderbird and trying again. Rebooting. Disabled Defender email filters for the smtp server all to no avail. Running upon Windows 10 Professional, Thunderbird 91.3.2 (32-bit) The email server is Exim 4 upon Debian Linux. Thanks for any help you can give on this. Regards Patrick