Users lose access to network share

We were troubleshooting an issue within a Domain Network with Windows Servers 2016 (1 DC and one File Server) and Windows 10 clients. Every so often the clients will not be able to access the file share on the File Server. Servers and clients are all on the same subnet.

A quick solution to the problem seems to be restarting the "Server" service on the File Server (which also restarts the "Computer Browser" service, which consequently produces a BSOD error in the event logs with stop error 0x1000007e caused by srv2.sys).

When the users report the issue, ping from/to the server works fine. Access to the share via IP (rather than UNC path) not working. Access to PCs folder from the file server works, e.g. \PCIPAdress\C$\Users\whatever.

We have removed Kaspersky from the servers (no change); we have disabled the Windows Firewall for the Domain (no change).

Note that previously, the same client had an issue with a Network Share where their multifunctional device was storing scanned documents; the documents would appear immediately on the server, but the clients could take up to 10 minutes before they could see it on their PCs via the mapped network drive. We resolved this issue by adding the following registry entries:

Hive HKEY_LOCAL_MACHINE Key path SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters Value name DirectoryCacheLifetime Value type REG_DWORD Value data 0x0 (0)

Hive HKEY_LOCAL_MACHINE Key path SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters Value name FileNotFoundCacheLifetime Value type REG_DWORD Value data 0x0 (0)

Hive HKEY_LOCAL_MACHINE Key path SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters Value name FileInfoCacheLifetime Value type REG_DWORD Value data 0x0 (0)

Any ideas on what else we can try?