Error establishing a database connection !

[choukri.koukhoud34]

Hello, i have a big problem, my blog was working well i'm using wordpress. suddenly my blog doesn't work i don't know why, i didn't change anything in the options, so my problem is that when i'm connecting to my website, the message below apears : Error establishing a database connection
I'd someone to help me because i have searched all solutions on internet but there is no issue.

So thank you very much i hope my problem will disappear