3-4 months ago our internet went down, technician came the next day to check. Changed the cable, still not working, so replaced the modem and all seemed ok. However we had usage issues, some sites would not load pictures, or not load at all and give errors such as: err_ssl_version_or_cipher_mismatch and err_ssl_protocol_error, which is something wrong with "security" of the site. Some sites would not load the log in areas, one site wouldn't let my payments go through, my smart tv wouldn't log into a new streaming service, couldn't get zoom meetings to work, etc.
Technicians came 4 times, always doing something with the cable but it never fixed the issues. I finally began to suspect the modem (either faulty or some restriction setting?) because I would have these same issues when my phone was on wifi, but if I went on data, or connected on wifi elsewhere, everything worked fine. I asked if we could try a new modem, rep said no everything looks fine on his end. Called the next day saying we would find a new provider if we can't try a new modem, was told no again by the same guy.
So we switched to a new provider, got a new modem, and surprise surprise the issues we were having are gone. Ironically one of the sites I couldn't log into was Fido's, otherwise maybe I would've posted here for help before switching. Since I can log in now, I wanted to post anyway so that if anyone else has mysterious issues, that tech support should be willing to try more options.