Bugzilla

No luck in duplicating what you see. But I do see one thing in you log that I ignored before but don't understand. After the point where it fails to run the "save to Sent2" url, I see an attempt to store a flag value on a message in Sent2. I don't see any "store" imap command so it appears this fails too.
Specifically it is ```creating protocol instance to retry queued url:imap://<your server>:993/addmsgflags>UID>/Sent2>1963>64``` which means it is trying to set flag value 64 (0x0040 == kImapMsgForwardedFlag) on message UID 1963
I don't see this url run when I send a message from here.
You can identify which message in Sent2 has URL 1963 by adding the column "Order Received" which actually lists the message UID.

Also, FWIW, after clicking "retry" the second time, it appears the the message got appended twice to Sent2, according to your log. I don't know if you ended up with two copies of the message in Sent2 or if your server saw the second one as an exact duplicate and deleted it.

No luck in duplicating what you see. But I do see one thing in you log that I ignored before but don't understand. After the point where it fails to run the "save to Sent2" url, I see an attempt to store a flag value on a message in Sent2. I don't see any "store" imap command so it appears this fails too.
Specifically it is ```creating protocol instance to retry queued url:imap://<your server>:993/addmsgflags>UID>/Sent2>1963>64``` which means it is trying to set flag value 64 (0x0040 == kImapMsgForwardedFlag) on message UID 1963
I don't see this url run when I send a message from here.
You can identify which message in Sent2 has URL 1963 by adding the column "Order Received" which actually lists the message UID.

**Edit:** I see the same thing if I forward a message in my sent folder. When I test with a server that does not include "forward" flag as a permanent flag (like your server), I see the same thing. The addmsgflags url occurs but no network activity occurs since the flag is only stored locally for the message. So this is probably not significant.

Also, FWIW, after clicking "retry" the second time, it appears the the message got appended twice to Sent2, according to your log. I don't know if you ended up with two copies of the message in Sent2 or if your server saw the second one as an exact duplicate and deleted it.