apple mail.app says: an error occurred while moving messages to mailbox (null) when trying to move to trash

apple mail.app says: an error occurred while moving messages to mailbox (null) when trying to move to trash

I searched and followed the instructions here:
https://help.zoho.com/portal/en/community/topic/can-t-delete-mail-from-email-client

The instructions did not work for me. The weird thing is that "sometimes,"  very rarely it will connect, and I will be able to move messages to trash, but only maybe 1/100 times.

I've poked through all settings in mail.app and zoho and I am running out of ideas, it is barely usable like this