We have also had this same issue starting after I updated the desktop client and the gateway on Monday. We have an internal site that has a link to Power BI. It would just stop on a white screen with a signin#code= added to the URL. Sometimes clearing the cache fixes it but we did have a couple people that had to do it again. We also saw the disableCDN parameter added to the URL sometimes. For a little while on Monday I could not export data from a table. We can't find a pattern on what fixes it, seems like it might be different for different computers. We tried different links like
https://app.powerbi.com or https://app.powerbi.com/groups/me/apps straight to the address bar. Usually this would bring up the Power BI service but had an instance where it didn't. We also had a guy with two computers, laptop and desktop and it worked on one but not the other.
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