Go to phpmyadmin and copy the following sql query:
UPDATE admin_user SET password = CONCAT(SHA2('xxxxxxxYourNewPassword', 256), ':xxxxxxx:1') WHERE username = 'admin';
The xxxxxxx character sequence is a cryptographic salt, it is saved in app\etc\env.php file
return array (
'key' => '525701df74e6cba74d5e9a1bb3d935ad', //cryptographic salt
I hope this solution works for you.