Zend certified PHP/Magento developer

Exception #0 (Exception): Notice: Undefined offset: 2 in vendor/magento/framework/Encryption/Encryptor.php on line 588

I am getting below error while admin login :

Exception #0 (Exception): Notice: Undefined offset: 2 in vendor/magento/framework/Encryption/Encryptor.php on line 588

I have installed php sodium extension, created new admin user but nothing worked. Please help me out.