This has happened twice, first on 2/21, and then again yesterday. Outbound emails from Apple mail (for all accounts) are suspended in the outbox. After trying multiple remedies (with Apple tech support) what fixes the problem is disabling SpamSieve completely (and closing/reopening Mail). After that, each time I re-enabled SpamSieve and everything then appears to work fine. Michael Tsai says that SpamSieve doesn’t do anything to affect outbound email, and he suspects it is a bug in the Mail app itself. Posting this in case anyone else is encountering this problem.
Thank you for information Jeff:
Please post Mac OS version, whether or not this is an Intel or Apple chip machine?
Thanks again for sharing.
Jenna
You had said that disabling the SpamSieve extension (in Mail’s settings) helped, so my conclusion is that Mail was internally blocked with something related to the extension. Quitting Mail would also probably unblock it.
Recording a sample from Mail would show what Mail is doing when sending is suspended, and this could be reported to Apple in a bug report.
SpamSieve can work fine without the Mail extension, so if this keeps happening you could just run Mail with the extension disabled.
macOS 15.3.1
Intel Xeon W
Quitting mail did NOT solve the problem. Rebooting the computer did not solve the problem. I tried all that. The first time this happened, the Apple tech guided me through every step you can think of, and we finally ended up disabling SpamSieve (temporarily). But if nobody else is encountering this problem, then it’s a mystery.