Hello Nev,
I'm sorry to hear that you're experiencing issues with AVG Secure VPN. In this case, I request you to change AVG Firewall network profile to private (open AVG Internet Security > menu > settings > components > firewall > customize > network profile > change all the network public to private), please go to Firewall customize settings again > scroll down > click on system rules > enable all the system rules if it's not configured, please click OK and check if your email is working fine with enabled AVG Internet Security/AVG Secure VPN. If the issues still persists, then I request you to change AVG Secure VPN location (open AVG Secure VPN > Disconnect > change location > select a different location and connect) and check with your email.
Best regards,
Alok.