Error Code: YAM

This error code can appear if a player's anti-virus is blocking Marathon's connection to their computer.

Players can work around this by either disabling their anti-virus when Marathon and BattlEye are running or by adding those programs to their anti-virus' allow list.

We also recommend reviewing our Advanced Troubleshooting: UPnP, Port Forwarding, and NAT Types guide for other potential resolutions.

Bungie