This evening got a phone call from a friend. He’s migrating data for a client from a broken laptop to the new one. Long story short the computer have one outlook 2010 with three email account. One google apps account with setting from Google Apps Sync, one google apps email with manual IMAP settings and the last one is gmail account with IMAP settings.
The second and third email can send and receive email normally, while the first email, the one that was setup by Google Apps Sync can not send email, even though it can receive email normally. Things get more horror when he check webmail and the email is on sent item. The email is on Google server but it is not sent to the intended recipient. He look closely and found that it has outbox label. So the email is on google apps email on sent item with outbox label. So who give outbox label on the email then?
I asked him to check are there any anti spam or anti virus? he said no antivirus or anti-spam program. but after he check on Add/Remove Program there is one antivirus installed but already expired so he uninstall the program. Try to send email again and it successful. So, when you get similar problem, check for anti spam or any email scanner on your computer and try to turn it off temporarily and see if you can send email normally, or if you have expired antivirus try to uninstall it first, if the email send/receive back to normal don’t forget to install the antivirus again. Hope this help.