Can't log in from launcher any more

Hello, from a few days back my son cannot use Minecraft launcher, when we select start using a Microsoft account, as we used to do before, it now says that it cannot initiate session.

The computer is a MacBook Pro early 2008 and OSX 10.11.6

Looking at the logs from the launcher I found this message:

"The device identity was rejected by Xbox services"

My son have been working fine on the same computer for the last 2 or 3 months since we bought the Minecraft Java editions license.

Any help appreciated.