Apex Legends Steam — anti-cheat error [4], Service Error 87

Since the update to EA Javelin Anticheat, Apex Legends on Steam displays this error when attempting to join a match or enter the Firing Range: “The client is not running the anti-cheat, or has failed the anti-cheat authentication. [4]”

 I have already tried verifying the game files; Steam consistently reports that 3 files failed verification.

The official installer (EAAntiCheat.Installer.exe) does not list Apex Legends, even though the game is installed via Steam.

In services.msc, the EAAntiCheatService appears as stopped with a "Manual" startup type.

When attempting to start it manually, Windows returns: “Error 87: The parameter is incorrect.” I also confirmed that C:\Windows\System32\drivers\eaanticheat.sys does not exist.

Could you help me repair or correctly register EA Javelin Anticheat for my Apex Legends installation on Steam?