@Shamazani Are you sure you connected both your PC and your phone to this router during the test and that they weren't connected to the guest network?
Try connecting the mobile phone to the WiFi of the router, turn off the mobile data traffic of the phone, turn off the VPN, turn off the firewall on the PC, and check whether the PC can be found in the mobile APP. If that doesn't work, you can try ping your phone's IP address from your PC to test connectivity.

  @DIDADI as i said, everything worked before i got my new c80, and i have the guest wi-fi disable, there is something in my new c80 that does not work with my vmr for the vlc, and yes i have re installed the program, yes its white listed in my antivirus program and firewall, the only new in here is my c80, if my old one c7 did not breakdown after 7years i would not have this issue :D

but thank you for your advise

best regards

update: i did re install everything and now it works, odd,