I constantly get an error message (using Apple Mail with Spamsieve on a Mac, all most recent versions of software) as follows:
The message “whatever” could not be moved to the mailbox “Spam”
The IMAP command “APPEND” (to Spam) failed with server error: APPEND Contains Deleted flag.
Most spam is handled correctly and gets moved to the Spam mailbox, but 4-5 messages a day throw this error. I then have to manually delete them from my inbox.
If someone could tell me what this means and now to fix it so that my spam gets filtered to spam I’d appreciate it!