Hello,
how were you informed about this problem? By e-mail? Phone, an app or website?
If you have this in writing, can you share this content with us?
I suggest you ignore this warning if it was a contact by phone, email or website.
In any case, try to restart the Internet Box!
If the problem was detected via an app, you can run the test again after restarting.
I rather assume a fraud attempt than any other problem.
If you still want to go to Number Safe, you can reset the box with a paper clip on the back or bottom.
Before resetting, I would report the problem to Swisscom by phone so that it can be analyzed and not transferred to other devices.
Best regards.