say that you have two guard sellerbranch and users, you can write your logout function like this in the LoginController
public function logout(Request $request)
{
Auth::guard('sellerbranch')->logout();
Auth::guard('users')->logout();
$request->session()->invalidate();
return $this->loggedOut($request) ?: redirect('/sellerbranch/login');
}
if you want you can check which guard is logged in and logout only that guard, but i used this snipped in one of my projects, i never had any problems loggin out both of them.