This happens from time to time, and especially if you open many mails at the same time (the “open all” button). Even with the Internal mail database error, you get the items attached to the mails, so it isn’t that much of a problem. I agree it should be something to look into as a bug fix, but for the time being it seems to be working as intended even with the error popping up.
i dont rly think this is the issue …. is true like a trying earn gold with selling items in AH so i have almost all the time some item in mail … but even when i have empty mail box i cant receive any letter…
not a single character can receive a mail from player.. not even in retail