Outlook - Sending reported error (0x80040201) Unknown Error 0x80040201

This would usually indicate that the Outlook PST is corrupted. The most probable reason could be PST file size above 2 GB. MS Outlook 2002 and its earlier versions have a file size limitation of 2 GB for PST, beyond which PST gains chances of being corrupted. However, PST file corruption can also result from other reasons too.

To repair the corrupted PST, Outlook installation includes a Scanpst.exe file. The file launches 'Inbox Repair Tool' that can fix most of the corruption issues associated with Outlook PST.

This is a hidden file, so make sure that the 'Show hidden files and folders' option is enabled to view the file. Further, you can follow these steps to start repair:

1. Close Outlook
2. Click 'Start' and then 'Find' or 'Search'
3. Type 'scanpst.exe' in the search box
4. Double-click the file to open 'Inbox Repair Tool'
5. Browse to the affected PST and specify the file name
6. Click 'Start' to begin repair
7. Click 'OK'

The Inbox Repair Tool(scanpst.exe) cannot repair the PST that is above 2 GB in size.

Via:
http://www.articlesbase.com/data-recovery-articles/how-to-solve-sending-reported-error-0x80040201-error-in-outlook-1753461.html