Today I attempted to log into webmail.shaw.ca using the both the latest Firefox and latest Chromium on Linux. In bot cases, after entering my login details and clicking "Sign In," the Sign In button went grey for a few seconds, then returned to its blue background without logging me in.
A subsequent attempt to log in using MS Edge on Windows succeeded, so I know the username/password combination is good.
Shaw Live Chat said "Linux is an unsupported platform." I do not accept this. The "platform" is the WEB; browsers are a tool for accessing content on the web. It should not matter that the browser, especially well-supported and standards compliant browsers such as Firefox and Chromium, is running on Windows, Linux, MacOS, Android, or Plan 9. They should Just Work. I can log in to dozens of sites, including eBay, Amazon, Proton Mail, cbc.ca/ctv.ca, SourceForge, GitHub, and LinkedIn using Linux. Shaw should be no different.