gmail was not available on 04 April: 500 System Error.

After a few hours I could log in, but the search in emails was still not working

On windows mobile the default client for windows exchange will ask separately for username, domainname and mailbox. Some other IMAP4 clients like qmail, that is o very good (and free) email client for windows mobile, require the username in the form DOMAIN/USERNAME/MAILBOX