A user does not get the realms invitation notification

Hello, everyone,

I have created a new realms and invited some users without any problems, one user in particular however does not seem to receive the invitation. His invite box indicates no pending invites.

He has already tried uninstalling and reinstalling minecraft luncher from the microsoft store and I have already tried deleting and re-adding the invite several times.

What should I do?

Thanks in advance for the support.