Mail from CMSB - Straight to Junk
You can google "email deliverability" and check out the details here:
Or use a third party mail sending service such as: https://www.sparkpost.com/
The IT guy might be right, the web host might not be configured to allow sending for the domain name your using - which will cause some servers to flags email as spam. You could also ask them IT guy what they need setup on your end to allow the emails to get through their spam filters.
Hope that helps!