Sent emails not Saved to Sent or Other Folder

This issue has existed for a while now. I keep receiving this message on my screen when I send an email from StartMail ( see attached ) This issue does not occur with other providers when using the same client to send emails. It happens on different computers that has a newly installed operating system and a fresh installation of Thunderbird. The issue is only with the sent folder and only for this email account. '''I taken multiple steps to correct this. ''' Tried installing Thunderbird on a fresh operating system installation and the issues persit Account Settings -> Copies & Folders. I have tried both Sent and Other. IMAP is properly configured to imap.startmail.com port 993. This should not matter because the issue is only to the sent folder. Sent folder set to Syncronized Sent messages not going into a different folder by mistakes because of any filter. Properties Repair Folder done Inside the profile folder under IMAP imap.startmail.com deleted Sent.msf, Sent messages, Sent messages.msf Click on get messages .......If I sent an email from the startMail web interface then the email is saved to the Sent Messages but the counter does not show there is a new email Again the issue only affects mt Startmail account sent folder. All the other accounts do not have issues. There is a messages that keep re appearing on my screen. Is this helpful ? The current command did not succeed. The mail server for account ........@startmail.com responded: [TRYCREATE] Mailbox doesn't exist: Sent (0.001 + 0.000 secs ). What gives I have both a sent and a sent messages folder but no messages are saved and if I am reading this right is telling me that the folder I have does not exist ? Also I am using Linux Mint 22.1 Cinnamon A few hours after my initial post I tried another client. Evolution client was configured and worked out of the box. There was no issues with emails being placed in the sent folder. Is Thunderbird broken ? I appreciate any help to correct this please. Thanks