Unable to Connect to Web Source With Credentials in Power Query

Deleted first of all, it looks like the query on your old PC hasn't been refreshed in months.  From the Query Editor, click on REFRESH ALL and see if it still works.  If it does work, click on the Web View tab and post a screen shot of both PC's (redacting any sensitive info of course).  Lastly, click on Data Source Settings on the Main tab in Query Editor and then Edit Credentials.  See how the old one is set-up compared to the new PC.  I'm not convinced your problem is authentication or that your problem doesn't exist on the old PC.  This will prove or disprove, I think.

Tim Scott's legacy wizard suggestions are not at all what you're looking for.  the legacy scrape is far inferior and you old PC was not using legacy.  Not sure why it's even being suggested.

To answer your question to me, I did figure this out - somehow.  Can't recall exactly.  But it had something to do with typing my password into the API credentials, I think.  I can't quite recall but it wasn't an obvious move.  After 2 years with no answer, I just started trying things and it worked.  Did it for a few other sites, didn't write it down, now I can't remember.