Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
I am also having the same problem. This was my first ever attempt at doing the PST import and spent a lot of time trying to figure out what was wrong. Apparently it's been broken this whole time! My first failed attempt was on 7/21/2022. I've tried a few times since then, including today, 7/28/2022. I even created a test PST that is only 2MB. Like everyone else, I get the Failed,MRSRemoteTransientError error.
I followed all steps in this guide and had no problems until the end when I try to run the import. It analyzes the file fairly quickly without any trouble, but then sits at the "Import in progress" phase for probably 20-60 minutes before it finally fails. I verified that the PST exists in our Azure storage. My mappings were validated successfully.
Hopefully if we get enough visibility here, we can get Microsoft to do something about it. If anyone finds a solution, please let us all know in this post.