What I said earlier doesn't apply to the, "this site can't supply a secure connection". I get this message every once and a while on the AT&T site. I have tried a few things that i read about to fix it, but nothing worked.
I finally found this:
......If Google Chrome is your window to the world of the internet, you must have encountered a “This site can’t provide a secure connection” error or an ERR_SSL_PROTOCOL_ERROR message at least once. The frustrating thing about this error (family of errors, really) is that there’s no easily discernible cause behind it a lot of the time. The SSL errors can pop up on the most popular sites as well as on the least ones. Heck, I’ve gotten one on here, on our website, and I can assure you our SSL/TLS configuration is up to snuff.....
https://www.thesslstore.com/blog/fix-err-ssl-protocol-error/