@Jaki It’s definitely not the browser itself as I am able to login to Skype with my current account and a new one I made just for testing without any issue. I do have a few more things to try before logging this as a bug.
Can you (either of you) please try logging into Skype with Shields (lion icon in the address bar) down and see if this makes any difference?
- Visit web.skype.com
- Click the Shields icon and turn the main toggle “off”
- Allow the page to reset then try logging in normally again