error 404 received after a poweroff of web server

Hello,

After a brutal poweroff of my web server and after restarting the wordpress, i receive the 404 Not Found when a try to log again with the password protected plugin.

Same message with the url http://mywebsite/wordpress/wp-admin

the redirect url is :
http://mywebsite/wordpress?password-protected=login&redirect_to=http%3A%2F%2F192.168.0.80%2Fwordpress%2F

i have access to the mysql database.
i suppose something has been locked by the poweroff,
How could unlock from this situation ?
Thanks

https://wordpress.org/plugins/password-protected/