Clearing the cache should work and we've done this in several instances and it has resolved the issue. I personally did the same as @BenHolmes1 but I didn't uninstall and re-install, or even restart the machine and its working as expected for me now.
I have been unable to login to either my Arc Ent or AGOL for a couple of weeks. Clearing cache, etc., have not worked. I have been upgrading to each new Power BI release, most recently on 11/30. I hope I have stumbled upon the reason. I just discovered I had two versions of Power BI Desktop installed -- one from the Microsoft Store and the other from the PBI download site ("click to run"). I have only been updating from the download site, but both versions appear to be up to date. Perhaps the store version is auto-updating. I don't recall ever installing from the store, but who knows. In any event, I uninstalled the click-to-run version and was able to login from the ArcGIS Maps visual. See The Best Way to Install Power BI Desktop - Excelerator BI.