push “dhcp-option DNS 188.8.131.52”
push “dhcp-option DNS 184.108.40.206”
in the server configuration solved the problem.
Openvpn server (type TLS), Nexus 5, OTA-8 (16.04).
I can go vpn online only via wifi, via gsm data only allows you to establish a vpn connection to the server and go to the tun0 network.
Server configuration is correct - other Android devices are working correctly.
Many thanks for any help!