How to solve the problem of not working single sign-on authentication?

I use advanced app and made in your project in a single sign, then tried to login on the frontend everything seems fine, but when logged in backend user was not logged-decided to try to login on the backend to check, but it turned out that the authorization does not work, just redirected to the main page not logged -.
Here is the code of the file backend main.php(all that relates to authentication)

'request' => [
 'csrfParam' => '_csrf-backend',
 'cookieValidationKey' => $params['cookieValidationKey'],
],
 'user' => [
 'identityClass' => 'common\models\User',
 'enableAutoLogin' => true,
 'identityCookie' => [
 'name' => '_identity',
 'httpOnly' => true,
 'domain' => $params['cookieDomain'],
],
],
 'session' => [
 // this is the name of the session cookie used for login on the backend
 'name' => '_session',
 'cookieParams' => [
 'domain' => $params['cookieDomain'],
 'httpOnly' => true,
],
 ],

Here is the code of the file frontend main.php(all that relates to authentication)

'request' => [
 'csrfParam' => '_csrf-frontend',
 'cookieValidationKey' => $params['cookieValidationKey'],
],
 'user' => [
 'identityClass' => 'common\models\User',
 'enableAutoLogin' => true,
 'identityCookie' => [
 'name' => '_identity',
 'httpOnly' => true,
 'domain' => $params['cookieDomain'],
],
],
 'session' => [
 // this is the name of the session cookie used for login on the frontend
 'name' => '_session',
 'cookieParams' => [
 'domain' => $params['cookieDomain'],
 'httpOnly' => true,
],
 ],