I figured this out. When I reconfigured my e-mail account in Outlook, I used IMAP settings instead of POP3. This was not how I did it before. IMAP works great if one wants to keep all e-mail out on the server and access it from various devices. That isn't what I do. I changed the profile to POP3 and the problem was solved. Still don't know why it initially failed two nights ago, though.