DNS resolving while working from home doesn't work accurate

In the current situation we are using VPN connections while working from home to get access to data in our company network. We are all using Windows 10 machines. We have some shared directories like "\ \fileserver.domainname\" . Many users have had the problem that the link to the shared directory. Instead they get the error "0x80070035 - The network path was not found.". I found out that this is a DNS issue, since it was still possible to access the server via its IP address. The problem seemingly arises totally random and is disappearing again after 10 minutes to several hours. What can be the possible cause of the problem and is there a solution or do we have to use the workaround with the IP address?

We have experienced this problem many times with Windows 10 and VPN users. The solution was to change the interface metric for the physical adapter to be higher than the interface metric for the VPN virtual adapter. By default, the interface metric is set to Automatic. Uncheck the automatic box and set the metric to 50 for the physical adapter, and do the same for the VPN virtual adapter, but set it to 25. Next, open a command prompt, using Run as Administrator, and issue the command ipconfig /flushdns. Or you can just reboot. This should make the DNS provided by the VPN the "master".