Error: 0x800CCC90 Cannot Send / Receive Emails - IT Support Forum

May be the account is corrupt or the inbox is corrupt. Could even be a corrupt email waiting for you on the server.

1. To fix account delete it and create it again
2. To fix corrupt inbox close Outlook express, search the computer hard drive and find your copy of inbox.dbx and rename it inbox.old or something. Reopening outlook express should rebuild the file (All your old emails will not be there)
3. To fix corrupt mail on the server log into webmail and remove messages that could be corrupt.
4. If you get ERR AVG POP3 Proxy Server in your error message then re-install AVG to fix the problem.