Cannot login due to Login Loop "Preparing Power BI... working"

To anyone who's still having this issue, we recently ran into it ourselves. We have some users synced between tenants and they are guest users with usertype "member" in the destination tenant. When one of these guest users logged into fabric/powerbi in the destination tenant, they were getting the infinite loop. These users are assigned a "Fabric Free" license on their source account in the source tenant. We found two methods that fixed this issue:

• Changing the usertype from "member" to "guest" fixed the issue. This option doesn't work for us since we need them to be usertype "member".
• Assigning a "Fabric Free" license to the user's source account AND destination tenant guest account stopped the infinite loop even when the guest is set to usertype "member".

I know this is an old post, but figured this might help someone experiencing a similar issue.

We had the same issue.  What was happening is that my AAD[1] account (PBI Pro Licensed) was a guest account in another AAD[2] tenant that I'm an admin over.  My account in AAD[2] was set specifically as 'User' instead of 'Guest' within AAD.  Once I swapped my account over to 'Guest', I was then able to log into the online pbi portal for that tenant using my AAD[1] account without issue.  

pauljevans , I think you're on the money there. The account stuck in the loop is indeed a guest account which was promoted to User via Powershell in the secondary tenant. 

Has there been a resolution to this issue? My teammates just launched an app but had some users with a different domain then our main office, is this related to different domains? or a local appdata issue? Thanks

Hi Anonymous,

I test it using IE and Chrome, which works fine. Please use Chrome to login in https://powerbi.microsoft.com .

Best Regards,
Angelia

I have this exact same issue.  I've used Edge, Chrome, Firefox, Safari, Opera on a mix of both Windows and Mac.  It's a guest account in the tenant, but still end up at this screen re-cycling forever.  Mine don't end after 2-3 cycles, I've let it go for 10 minutes... never ends. 

I've just run into this one myself. When sharing a report from one tenant with a user from another tenant it goes into a Preparing PBI loop. I have a hunch, that it has to do with the BYO Power BI license. The user is not licensed on the target tenant but instead is bringing their own PBI license to the game. 

This has been tested in an incognito environment. 

The Report starts loading, the Frame and event he visuals start loading, but then it sends the user to the sign-up screen, walks through the sign-up process with "you are already signed in", sends the user back to the report and goes into a Preparing Loop> Load pbi, load frame (with target tenant theme), load dashboard or report, start loading visuals, go back to Preparing Power BI, wait, load frame, load dashboard, etc. 

The redirect loop happened, at least in my case, because a Power BI license was not assigned to my account.

I am guessing Power BI tries to assign the license (one of parameters in the redirect URL had the web_nolicense_redirect value) and fails. I tried to assign the license manually, and got error License cannot be assigned to a user without a usage location specified.

Google and found this: https://answers.microsoft.com/en-us/msoffice/forum/all/license-cannot-be-assigned-to-a-user-without-a/1239da04-1bf7-439b-a4b1-016cfbc2fa0d

Set the usage location for my user, manually assigned the license (this time it worked), and after that, there was no redirect.

Removed the manually assigned license, re-tested, back to redirect loop. For some reason, the automatic license assignment still failed despite the usage location being set.

Hope this helps somebody