I ran into the same problem, then I came across this.
ProtonVPN
The configuration file provided by ProtonVPN will not work as-is. Specifically, 3 changes are needed:
Comment out "setenv CLIENT_CERT o" by adding "# " to the beginning of the line
Comment out "up /etc/openvpn/update-resolv-conf" by adding "# " to the beginning of the line
Comment out "down /etc/openvpn/update-resolv-conf" by adding "# " to the beginning of the line
You will need to use the OpenVPN / IKEv2 Username & Password (not your account username & password) (account.protonvpn.com/account#username)
ProtonVPN
The configuration file provided by ProtonVPN will not work as-is. Specifically, 3 changes are needed:
Comment out "setenv CLIENT_CERT o" by adding "# " to the beginning of the line
Comment out "up /etc/openvpn/update-resolv-conf" by adding "# " to the beginning of the line
Comment out "down /etc/openvpn/update-resolv-conf" by adding "# " to the beginning of the line
You will need to use the OpenVPN / IKEv2 Username & Password (not your account username & password) (account.protonvpn.com/account#username)
"