Lately I am having trouble using my IMAP mail account with Thunderbird 68.6.0 (64-bit GNU/Linux). In particular, it doesn't seem to be possible to move certain folders via IMAP. When I try to do so, Thunderbird pops up the following system notification: [CANNOT] Renaming not supported across conflicting directory permissions (0.006 + 0.000 + 0.005 secs). (The last three numbers vary from notification to notification.) A cursory web search for this error suggests that the problem is with directory permissions on the server (which is running Dovecot). However, two pieces of evidence would appear to discount this explanation: 1. My sysadmin has checked the permissions for my folders on the mail server and insists that everything is in order. 2. I have no problem moving the same folders from another IMAP client (Claws Mail 3.17.5). There doesn't appear to be any commonality in which mail folders are affected by this problem and which aren't. (At least, I haven't noticed any pattern.) The problem occurs even when Thunderbird is started in safe mode, with all add-ons disabled. Should I report this issue as a bug with Thunderbird or are there some other troubleshooting steps I or my sysadmin can do?