We are having issue with Symantec, for some reason to me, we get blocked all the time. I've contacted them countless time, they can't tell us why we are getting blocked, they unblocked us and there a few days later it's blocked again.
Symantec "Anti-spam" is used by Microsoft, Universities and some Company, probably your university just plain reject the email based on symantec "intelligent" spam filter.
If you can do a test using another email like Gmail, you will not have any issues.