Minecraft LAN issue?

First, make sure every player that wants to join is connected to the same network, then choose a host device that will run the world, and make sure everyone joining is running the same version of the game as the host.

Start a LAN game:

1. Press Play
   
2. Create a new world or edit a current world by pressing the pen icon
   
3. Go to multiplayer and make sure that “Visible to LAN Players” is enabled
   
4. Start the world by choosing Create or Play
   

Join a LAN game:

1. Go to the Play menu
2. Click the Friends tab and look for available LAN Games

If the issue still persists please contact Mojang

Alrighty, I'm glad to hear that this has been resolved! I'll close this thread in about a week unless you've got anything else related to this that we can help you out with.

Ah thank you so much this works!

Question: on your phone, is the app permitted to access your local network?

Check your mobile device settings outside the Minecraft app, and make sure that the app's permissions include "Access to Local Network". That should hopefully fix the problem.

Let me know if that doesn't work. I'd also appreciate whether the phone is either iOS or Android to see if I can find more specific guidance for you.

You may want to reach this to Radmin VPN support.

https://www.radmin-vpn.com/support/

I doubt that Mojang is capable of assisting for the same reason. (You’re using a third-party program). However, you try your luck and can contact them here:
https://help.minecraft.net/hc/requests/new

Some links lead to a non-Microsoft websites. The page appears to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.