This error is only in relation to Microsft Exchange servers.
Recipients Exchange Server incoming mail queue stopped
Like almost all Microsoft Errors, the description doesn't give you much. It's typically due to a connection problem, however the only way to confirm the issue will be to contact the server administrators.
Unfortunately, with out knowing the exact issue, resolving this can be quite difficult. It requires contacting the server administrator to determine the reason for the error. Perform a WHOIS for the destination mail server to get contact information.