Do you every time get the error...

Probably while user model is calling , an exception is threw.

Here is Auth::logout() method..

/* \Illuminate\Auth\Guard */
	/**
	 * Log the user out of the application.
	 *
	 * @return void
	 */
	public function logout()
	{
		$user = $this->user();  // I think that  this point returns throw "Error connecting to database"

		// If we have an event dispatcher instance, we can fire off the logout event
		// so any further processing can be done. This allows the developer to be
		// listening for anytime a user signs out of this application manually.
		$this->clearUserDataFromStorage();

		if ( ! is_null($this->user))
		{
			$this->refreshRememberToken($user);
		}

		if (isset($this->events))
		{
			$this->events->fire('auth.logout', array($user));
		}

		// Once we have fired the logout event we will clear the users out of memory
		// so they are no longer available as the user is no longer considered as
		// being signed into this application and should not be available here.
		$this->user = null;

		$this->loggedOut = true;
	}

Yes every time I logout!

It is strange because if I return to the login page, the user seems to be logged out. I can login correctly again.

I have also tryed this:

if (Auth;;check()) { Auth:logout(); }

But anything changed!

Always "Error connecting to database"

Maybe my db structure is not compatible?

is there a standard schema to check?

I had the same problem because I too was getting the same error as you. Since you posted this 2 months ago, I am assuming that you have already figured out the answer but I am posting my solution here just in case other people have trouble figuring out the answer.

The user table must have updated_at column (datetime). Using Eloquent, all tables must have created_at and updated_at column. In this case, Auth can log out successfully but it cannot update the column updated_at if there isn't any and that is where "error connecting to database" comes from (You can find it in laravel.log).

If there is a problem logging in a user (Auth::attempt), Eloquent assumes default primary key called "id". If the primary key in your table is not "id", then add the following in User model.

protected $primaryKey = 'your primary key column';

Note that "K" in primaryKey is uppercase.