[CentOS] smba shares are unreachable once or twice per month

Hallo, I ve a problem with my samba-server. We are using a centos 7.7 with an samba exporting samba-shares. Logins are managed by our Windows-AD. The samba server has only the function to exports hares. Windows clients are Win10 patched every month. Our problem: Once or twice a month shares aren't akctive any longer and reachable for the Window-Clients. Network can nor be a reason because the same directory exported via NFS is reachable for all Linux-NFS-Client. Normally we disconect and connect the Samba server in the AD and after a reboot the shares are working again but that cant be the solution ;-) Can anyone give me hints hwo to anaylse and solving the problem.

Thanks Ralf