“Unable to move message” email error

I have both an AOL email account and Gmail account linked to my iPhone XR running 12.2. They worked fine together until this week, out of nowhere. I used to be able

to move messages from Gmail to a saved folder on my AOL account but now I get a message that says “unable to move message - This message could not be moved to the saved mailbox”. I have already updated iPhone software and deleted and reinstalled both email accounts, no luck! Any input would be helpful.

Thanks!