I have 2 computers, one with Windows 10, and the other using Windows 8.1, both executing Firefox 74.0. The CIBC Online web loads an inset window with a error message saying the web site is not available on the W10, but loads properly on W8,1. With Google Chrome the CIBC Online web loads correctly on either W10 and W8.1. I expect that the profile has some differences. I don't know how your debugging facility works else I would have tried it. Can I switch the profile from W8.1 to W10? When I load CIBC Online Banking website I use the Sign On option on the right side near the top.