This guide applies to the following error that may happen to any data source in Data Studio:
This was a reauthorization request for user account xxxxxxx but you logged in as UserName (yyyyyyyy) instead. This authentication was not stored, please try again.
This may come up in cases where the authentication was changed for the Data Source in a significant way (such as moving major API versions or changing how the user name is stored).
To address it, you should completely log all users out of the data source (including any and all teams):
And then log back in with the account you wanted to use going forward.
In some rare cases, you may need to revoke the connector as well, and then reconnect that and log back in. For instructions on how to revoke a connector, see "Revoke your access" in this article: https://support.google.com/datastudio/answer/9053467?hl=en
You can then reselect the connector from the partner list and re-authorize it, which should also ask you to log in again.
If you continue to have issues after trying the above actions, please submit a request to support so they can manually remove your tokens to reset this. Please note in the request that you already completed the steps in the article.