Message "xyz" Could not be Moved to the Mailbox "my email address"

Why am I seeing these error messages and how or who do I contact to fix them?:

I use Apple mail client with all my folders "on My Mac" and it's with Sky.com email who uses Yahoo servers I think. I used to have no folders set up on my Sky.com web platform and then a few yrs ago I created them form the advice of Level 2 but deleted them, I can't remember the exact reason but there was good one for doing that.

Ever since going from Mojave to Ventura I get warnings like:

1|) Message "xyz" Could not be Moved to the Mailbox "my email address" IMAP command, append (to inbox) failed with server error: APPEND contains deleted flag (the email was in a wrong folder on My Mac and I tried to drag it to the inbox)

or

2) 500 Messages could not be Moved to the Mailbox "name of mail folder on My Mac"

Mail was unable to open this mailbox on the server "map.tools.sky.com"

The server returned the error: SELECt error - fFolder does not exist or server encountered an error (these emails were in the wrong folder and again I tried to move them to the correct name folder)

Thanks