Company domain email addresses unable to send emails from our WP site

Hi,

I’m using this plugin and when I enter a company email address, such as [email protected] (also anything that ends in @convertmedia.com) for the “From Email” field, an email will not be sent.

If I enter an email address that ends in @gmail.com, it works. This problem began occurring once our development site and main site were merged.

Any help regarding this would be greatly appreciated.

Best,
Jordan