Exactly what sort of errors do you see? Can you post a screen capture of such an error (drag an image file into a reply while you are composing it)? As a somewhat new forum user you might not be allowed to post images yet, I’m not sure how that aspect of the forum works. If you cannot post screen capture image, then please write down exactly what error appears, and in what sort of window.
I’m also not sure what role a browser plays when starting SketchUp Pro 2020; can you clarify that?
Close your browser, open SketchUp, sign in, then Alt-tab to see what applications are open. Is your browser now open? If it is open and apparently has a window that you’re not seeing, read this post and try something similar to retrieve your browser window:
If your browser isn’t open, or it’s open and has no windows, go into the Windows control panel, where you can set your default web browser. See what it is currently set to, and try changing that to Chrome or Firefox, or a recent version of Edge.