cPanel systems do not like it when you change your MX records. cPanel assumes that if you re-driect your mail (by changing your MX records) you no longer want to use its mail service, so it turns off your email.
Detail & Fix:
If you manage your company's email by logging into a administrative panel from your hosting provider, chances are you are logging into a cPanel system. It's very popular among hosting providers. With some hosting providers you will see a cPanel logo, other companies may have customized the software so its hard to tell if you're using cPanel.
Either way, you will want to go into the DNS settings (DNS Zone) and change Mail Exchange (MX) record(s). You will want to first add our MX records and then delete the ones that were there. We will provide you with a list of our MX records to add.
When you change your MX records in cPanel (let us know if you need help doing this) you should see a section called Email Routing:
Make sure you select Local Mail Exchanger:
By selecting Local Mail Exchanger you are telling cPanel to keep using the existing mail service, even though you changed the MX records to point elsewhere.
Save your changes and allow them time to update.
Please contact us if you have any questions.