New users can't connect locally but can through My Cloud

Hi,
When I create a new user, I set up for them credentials (name and password) to connect locally, and then I also activate their MyCloud access by sending them an email invitation.
Users I create like this can access the NAS through My Cloud, however it’s impossible for them to connect locally, as it says that their credentials are wrong (which is false, I also tried my self to disconnect from my admin account and connect with their credentials (which I created) and this also give me an error message stating that these credentials are wrong).

Any idea where this issue is coming from and how to solve it?

Thank you for your help

one thought: The credentials for the App and local access are different.