Email Issues

[serverhenry]

I have a friend that is on my dedicated server and he started experiencing email issues. At times his email will work, but then it won't. Sometimes he can receive email, but not send (issue with outgoing server). He uses a Mac computer, and I'm not sure if this is what started the issue. He has two different ISP's, one at home and one at work. He is experiencing issues with both. I went into his work the other day and tried to fix it without success. I even added their email address to my phone to test it. When I was on my cellular network I had no issues. Once I connected to their WiFi...the issues began.

He is frustrated, and so am I (for him). I am trying to figure out what to do. I have a VPS that I could move it onto, but I'm not sure if that would help.

What would everyone recommend? Should I put his email on a different server and keep the website where it is? Any info/input/suggestions would be great. I am at a loss. Thank you.