SQL Server installation no longer visible to the client

I am running UrBackup server for more than a year now using it currently for 15 client hosta (both, Linux and Windows).
I have an issue with one host running MS Windows Server 2019 Standard with MS SQL Server 2019 Standard.
Initially, everything was fine with the backup, all windows components and folders were backed up as per configuration, including SQL Server databases. However, since like couple of months SQL Server databases are no longer being backed up and I cannot select SQL Server from component selection in UrBackup client, because is is not listed at all like SQL Server was not installed on this machine, which is not the case.
I cannot remamber any significant configuration change anywhere, which could cause such behaviour. Of course Windows Update is running on the server doing its duties, so maybe SQL patch has caused this? Also, automatic client upgrade from 2.4.10 to 2.4.11 happened in the meantime, but I don’t know if that had anything to do with my problem.
I have tried to fix it by uninstalling and than re-installing client, but no luck so far.
Any help would be appreciated.
best regards

Does it appear if you run vssadmin list writers? If not it is a VSS issue and not a UrBackup issue…

spot on! vssadmin did not list SQL Server VSS writer. I have checked few things and the issue was, that SYSTEM user used by this service did not have sysadmin role in SQL Security setup. After fixing this and restarting VSS service everything looks perfectly OK again.
Thank you!