Debugging error

Username (e.g. epiz_XXX) or

my users reported this

so I thought there was a problem with the wp-config file
so I tried fixing information in the wp config file but got an error of establishing database connection. me frustrated decided to delete the wp-config file and upload an backup but got this
(please specify the website or account you are asking about)

Error Message

what do I do?

2 posts were merged into an existing topic: Critical error in website