mbsync is failing to delete messages from Fastmail

I am attempting to move messages between folders, and it is deleting from the inbox and uploading to the Archive folder. However, while the upload works, deletion is failing: IMAP command 'UID STORE 13345 +FLAGS.SILENT (\Deleted)' returned an error: Permission denied _

[commit] branch 'wip/includecmd' created

The branch 'wip/includecmd' has been created at 9e9aa1b. ___ isync-devel mailing list isync-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/isync-devel