PPSSPP Ad-hoc Server is a feature that allows the emulator to simulate the PSP's local wireless multiplayer functionality. It enables players on the same network—or across the internet via VPN—to join the same game lobby for cooperative or competitive play. Core Functionality How to play multiplayer games with PPSSPP - GitHub
Ensure is set to localhost (or 127.0.0.1 ) on the host device. adhoc server ppsspp