Error code

Steam -138

STEAM-138
Game/Platform Error· An error code shown by a game or gaming platform/launcher.

What it means

Steam's embedded browser cannot load a page — displays "Error Code: -138 Failed to load web page (unknown error)"..

How to fix it

  1. Temporarily disable third-party firewall/antivirus.
  2. Clear Steam browser cache and cookies in Steam > Settings > Web Browser.
  3. Restart Steam.
  4. Switch Steam to Big Picture mode then back to Desktop mode.
  5. Flush DNS.
  6. Reinstall Steam if the issue persists.

Not affiliated with Steam. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.