indexing not working on URL path

When entering a share where Serviio can find photos or music, there is nothing found by several client systems. If I change the URL path to a driveletter/foldername, everything works fine. \\sbs2008\song$ does not work while M:\SONG does.
I prefer to enter URL path instead of a reserved driveletter.
Only domain users and domein admins can access the shared folers.
Is there something going wrong?

[DenyAll]

Permissions perhaps?

Try having Serviio log in as a domain user: run services.msc, select the Serviio service, select Log on tab and change the user Serviio logs in with. After doing so, restart the service and test.

Thanks! That was the solution!