We have some test cases to validate email body content after triggering some emails from our test system. Previously we used UI automation with Gmail and Yahoo, but as we are running our test in different servers (Different IP address) Gmail and Yahoo are asking for the two-factor authentication and human verification which we can't handle from our test automation.
Also we cant use
Javax.mail as the SMTP ports are blocked from our firewalls.
So could some please suggest a good email inbox to continue our test without any interruptions.