A player is missing
The player must enable visible to other players in Valheim's in-game map settings. Press M to open those settings.
Dedicated-server operators
Valheim WebMap support.
A public download is not available yet. The installation and configuration guides explain the package layout and data-exposure boundary.
First checks
Start with the boundary that failed.
A configuration change reverted
Stop the dedicated server before editing the generated BepInEx configuration. Changes made while the server runs can be lost on shutdown.
The browser still shows the old interface
Assets are versioned. First confirm that the server loaded the expected version, then use one hard refresh as a diagnostic step.
A feature or control is absent
Server-wide feature switches remove both the disabled data and its matching browser controls.
Client boundary
Browser viewers do not install a client mod.
Valheim WebMap runs on the dedicated server and serves the browser companion separately.
Unofficial community mod
Valheim WebMap is an unofficial community mod. It is not affiliated with, endorsed by, sponsored by, or supported by Iron Gate AB or Coffee Stain Publishing AB. Valheim and related marks belong to their respective owners. Use of mods is at the user's own risk, and compatibility with future game versions is not guaranteed.
Do not expose WebMap blindly
Normal viewing can expose map, player, chat, and server state. Do not forward a port to the public internet until you understand and configure the access-control, encryption, reverse-proxy, and hardening boundary for the exact release.