I have Gigablast service and just downloaded and set up a VPN service. Everything works except sending email. I have a Cox email account and use Outlook. I can receive emails with no problem. And, I have a separate Gmail account that sends and receives with no issue. Are there any special settings I need to use to allow Cox email to go out?
I have this problem as well. VPN on, can't send. VPN off, sends just fine. I had an issue with using COX email at my work early in 2020, and best I could find out, was that COX requires a "reverse DNS" lookup from the server that is sending the mail, and our IT folks had turned off that function with our servers. After much complaining, the IT folks at work eventually got around to make that happen again, and then mail started sending once more. Perhaps when on VPN (like at home), this Reverse DNS doesn't happen?
VPN providers sometimes restrict certain ports, such as email, to prevent malcontents from using their VPN service to freely spam, phish or infect addresses. If a VPN provider becomes a source of maliciousness, service providers, such as Cox, could blacklist their IP address. This would be bad for their business.
You'll need to contact your VPN provider to verify your intent and allow your port.
