Troubleshooting Outlook Express Error 0x800420CB
You may get the following error message:
  • Message Could Not Be Opened From Outbox Folder, Account: pop.yourname.
  • MailAccount',Server:'', Protocol:SMTP,Port:25,Secure(SSL):No, Error Number:0x800420CB


The usual cause of this problem is an Outbox.dbx file which has become corrupted. To fix it,
  • Click Tools
  • then Accounts
  • Click the Mail tab
  • Click a duplicate mail account, and then click Remove . Keep doing this until all duplicated have been removed.
  • Click Close
Still having problems with this error message? Try renaming the Outbox.dbx file, although this will permanently delete any messages still in the outbox.
  • Close Outlook Express.
  • Right-click the Start button on your PC's desktop
  • click Find or Search
  • Search for the Outbox.dbx file
  • Right-click the file, click Delete, and then click Yes
  • Start Outlook Express, and then try again