From Backup Server all is well. I opened the case #07277048, but we can't find the error so far. It happens since we updated VBR to 12.1.2.172.
Both servers are WS2022. I have reboot both servers, disable Windows Firewall, disable UAC,...
Ok, solved! The "Veeam Mount Service" was stopped, and gave an error when try to start (the file didn't exist, it's as if after the patch to the latest version it had been deleted).
I opened a cmd with admin privileges and run "sc delete VeeamMountSvc", copied the package of Veeam Mount Service from Backup Master, and installed the package.