I lost again my connection today so I spoke with the NordVPN Team.
They asked me to send the log and to :
Change the DNS in order to use the NordVPN DNS (previously I used the DNS of Google)
Download any UDP configuration file, open it with any text editor and then remove the following line:explicit-exit-notify 3 because Gl firmware doesn’t understand that line therefore causes the issue with UDP configurations.
So I will test this to see if I can keep my connection now.
Ahhh, interesting! I checked the files already in my router and none of those have the “explicit” line. However, I just checked the zip file I have on my PC and they do indeed have it!
So, at some stage Nord must have updated the files, as I downloaded a new copy after setting up my router…unless this line is somehow removed in the upload process (which I doubt).
Bottom line is none of my ovpn files have the line and I still lose connection.
Also, I believe this line is only included in the UDP files but I also get disconnects using TCP.