Outlook email problem with attachments

[AC Question]

I have a Galaxy S5 and use Verizon services. My phone has both g-mail and outlook services. Yesterday my outlook stopped sending emails with attachments and even when I replied to an email while WiFi is on. When I turn WiFi off everything works normally. G-mail works fine. Prior to yesterday I had no issues like this since I got the phone in July. My wife has the same problem at home. However connected to WiFi at work she does not have this problem. Any help will be appreciated