Internal Exception: java.io.IOException: An existing connection was forcibly closed by remote host

My son has been building a Minecraft world on his Windows 10 PC. When he selects 'Open to LAN', I am able to connect and join him. After a short period of time (5-10 minutes), I get disconnected from his world with the following error "Internal Exception: java.io.IOException: An existing connection was forcibly closed by remote host". If I then close Minecraft and try to reconnect I am unable. I am only able to reconnect to his world, if he also complete closes and restarts Minecraft also.

The problem is reproducible and occurs every time.