Issue with VPN connection on client device

I have OpenWRT configured to connect to NordVPN using Wireguard.

From one of the client devices I sometimes connect to NordVPN separetly using the Linux app.
This has been working for quite a while and it has stopped working recently. I can connect and I can also reach the DNS servers which are configures correctly. But I can't load any web page.

I found out that the connection works when I connect to a different wifi network. So it is apparent this has to do with the OpenWRT router I have.

Are you asking for help with your NordVPN android app?

The NordVPN android app works fine even when connected to the same network.
I only have the problem with the NordVPN client on my Linux machine.

Can you connect using OpenVPN to check, whether DPI is working?

When I change the OpenWRT VPN connection from Wireguard to OpenVPN, then I can connect freely with my Linux client using NordVPN app.