I use Outlook Express. I can send, but not receive. I have deleted the 15 million emails that had never been deleted, but still can not receive. I have been told I have a corrupted Inbox file. Something about the Inbox.dbx, but I don't know or how to correct this error.
Send or recieve any messages is just because of oversize file or may be damage file. 15 million emails you have deleted but have you emptied your deleted emails folder as all the deleted data saved in it and it means no size reduction. So try above shared steps by Marshal otherwise try some paid solution for that.