I have been using netmaker for a few weeks now and rarely (like 1 out of 20 times) when a netmaker client on windows does a join, it will be able to ping the central netmaker server ip inside the vpn network but it will not be able to ping any other clients inside the vpn network (mix of clients using central server as relay and other clients in a mesh network). The only workaround I found is leaving network using leave command and joining it back with join command a few times until everything works. (I automated it with a script so its not a big issue). Hopefully the issue will be resolved with the new windows client

same issue

also disconnect command will randomly break the vpn and only leave+join a few times will fix it