In this case, you can run exim on another alternative port something like port 26 or 587 rather than the default Port 25. Below are the exact steps do to so:
1. Log in to WHM. (http:// serverip:2086)
2. Go to Service Manager.
3. Check the box for Exim on Another Port.
4. Set the port to 26 OR 587.
5. Click save.