Openvpn appears to connect but does not allow any traffic

Hello, I’m trying to set up openvpn into my workplace. I have:

services = {
    openvpn.servers = {
        office = {
            config = '' config /root/office-untangle.conf '';
            autoStart = false;
            updateResolvConf = true;
    transmission.enable = true;
networking.networkmanager = {
    enable = true;
    packages = [ pkgs.networkmanager_openvpn ];
networking.firewall.enable = false;

and /root/office-untangle.conf looks like:

resolv-retry 20
keepalive 10 60
ns-cert-type server
# remote-cert-tls server
# comp-lzo
verb 1
explicit-exit-notify 1
dev tun
proto udp
port 1194
data-ciphers-fallback AES-128-CBC
remote officeuntangle.<<mycompany>> 1194 # public address 
remote <<IP address>> 1194 # static WAN 1
ca /root/office-untangle/ca.crt
cert /root/office-untangle/office.crt
key /root/office-untangle/office.key
auth-user-pass /root/office-untangle/office.cred

where items in << >> are omitted here for security.

When I systemctl enable openvpn-office, it appears to connect; my manager (a network engineer) says my netstat -rn and cat /etc/resolv.conf both look good, but no traffic will go through the VPN; it all just hangs. If for example I ping the DNS, or try any curl, ping etc. commands, they all just hang. Any default traffic (i.e., to addresses outside our office network) continues to work. It seems that the tun0 device won’t actually pass any traffic. Others are using the VPN, albeit from W*&$%#@, not from a NixOS client.

Any ideas?

This happens to me too. Did you find a way of fixing it?

here my post: Can't resolve VPN with OpenVPN

Shot in the dark, but have you tried doing this without networkmamager? Networkmanager has its own VPN config to my knowledge, it may mess with where traffic goes.