MS OneDrive App not working On iPhone, how to solve?

I have been looking for some answers in the community already, but cannot find an answer to my specific question. Since some time (the last update of MS OneDirve?) I'm not able to access my privat OneDrive on my Iphone. I can login, but after login in the wheel keeps on running trying to "load" the files. For my business OneDrive the problem is slightly different. I cannot login as it does not go further after using the Authenticator. In other words: I cannot access my files at my Iphone anymore. On my desktop it works fine. Using Outlook on line and choosing OneDrive on line, it works.

I re-installed the OneDrive app on my Iphone several times, but it does not work.

What is the solution?