Yii2 login session

hey there
i upload my advanced project and have an issue with login user in backend.
use logged in successfully but it seems there is no session to keep use logged in.
so after login, the screen show me the login page again.

I use same csrfParam at frontend and backend.

there is no problem on my localhost.

sorry for my weak eng.

thanks

Check any required folder permissions.

thanks for response.
i checked the permissions, no problem with them

any help? please