No one in our organization can send emails with attachments. Emails without attachments go through fine, but if an attachment is included, an error appears in the Server Failures folder under Sync Issues. The error is "The following message had an error and synchronization of it was skipped (0xc0090081)".
We are using Symantec Mail Security, which we shut down to try to troubleshoot the problem, and now that fails to load.
Any ideas as to what to check? I'm sorry I don't have more complete information, but I'm helping someone try to figure this out. I'm not the admin myself.