I will say it is your VPN. Nothing else is at fault.

Comcast require you to connect to the internet using their internet service to send mail. the VPN hides your real connection IP and offer some fiction. So Comcast refuses connection.

Google are more understanding, but exactly where in the world is your VPN dropping you out into the internet. Google get all antsy if you live in Brazil and the VPN is suggesting you are connecting from Romania all of a sudden for instance.

Then there is the question of how or even if your VPN supports the required ports for email. The world wide web ("The Web") uses different connectivity port numbers that email and some VPN's do not support any ports but those used for the web. Others only support email after you contact them and make special arrangements.

The real question is who are you trying to hide your "real" location from? Google, your ISP, Facebook, Twitter, linkedin, ebay, amazon and your online food ordering and other purcheases et al all have those details, supplied by you and get antsy when your details you supplied and the ones from your connection don't match. Then their are the monogamous web sites. Is that you are from the eastern united states or a Comcast customer all that interesting to them beyond having an idea of their audience? For a number of them you will have supplied a Comcast email address fr your account so they already know you are a customer. Comcast email addresses are not free.

Much money is being thrown at VPN's as a "security" feature. But consumers need to actually question what they are being sold. This forum reports you use Firefox. All web sites get access to that information from your user agent string.

So when your on a web site look for the padlock on the location bar. Those connections are encrypted, from your device to the web server sending the information. Would another layer of encryption help. Probably not.

do you really browse the internet? Most folks these days spend their time in social networking. They have already given them more about themselves than you would like to consider and a VPN offers no additional help there. Anonymous web sites where you know nothing about the operator, they know nothing about you other than the IP address to send messages to. A VPN obscures that, but as you are seeing that obscurity comes with a dash of inconvenience. You task is to decide if that dash of obscurity is actually worth anything and certainly worth the additional effort to set things up.

Add to that the fact that almost every web site has a "share" this link with those facebook and twitter icons. every one of those visits is added to what the social networks know about you as your visit is recorded. A VPN offer no help there either as say facebook already has a cookie on your system to identify you. They do not need to know the IP address, other than to guess you are traveling and offering adds for Romanian cafes.

Having said that a VPN between you and your employer is an excellent thing as nothing of the connection ever gets to the public internet without it being encrypted. It is like having your own set of wires that connect you to your employers network. The types of VPN's being offered however do only do that tunneling until they get to the "drop off point" and eventually drop your connection onto the public internet, thus obscuring your original IP address allocated by your internet service provider.

Thanks. I have personal reasons for use of VPN. But I've had them for years and I've had Firefox and Thunderbird for years too and never had a problem until recently. To me that says a software update by someone, I just don't know who. It's not the VPN. I've talked to them already. I usually set my VPN to a US region. Getting responses from Xfinity is not easy. They will deny everything and contacting Google, they don't respond directly either. But I'm trying to contact them and waiting for Xfinity to say something too.