iOS Error: “Cannot send mail. An error occurred while delivering this message”

reference earlier post for detail:

Cannot Send Mail An error occurred while … - Apple Community

I am having the exact same issue described in the link above (also detailed below). Has anyone found a solution?

Company exchange email intermittently gets this error when sending emails: “Cannot send mail. An error occurred while delivering this message”. But the email still sends to intended recipients. Problem happens on Wifi or Cellular with a good connection. Tried numerous troubleshooting steps including updating iOS, deleting and re-adding mail account, reducing # days of mail to sync, restarting phone, deleting mail app and reinstalling mail app after deleting all mail data, etc…

Any support would be appreciated! Thank you.