@Joseph-TP I run my network with fix IP's. DHCP server is running, but only for guests. All my own devices I have set with fix IP. I have tried the VPN server issue again. Before I had set Router...

@Joseph-TP WAN address is fix set. TPLink router is connected by LAN cable to Deutsche Telekom Speedport. At Speedport the IP is fix set for the TPLink Router. To your points: 1. There is no setting...

I have set OVPN server on the router to access my local network. Connection is working from Android phone and Linux computer as I want. But after reboot of the router I can only establish the VPN...