Did you enter the right mysql server ip in your server.cfg?
yes the server is working.But this error bothers me
that error is just one of those error that stay there and really hard to fix i would recommend not touching it if its not affecting the server 
It looks like you entered the wrong MySQL host or your MySQL (database) is offline
No because players are currently connected.Just I do not know where the error comes from because everything is good
It has nothing to do with server players connected it’s with your MySQL server aka database
so I do not see where the problem comes from
You’ve not provided any details regarding your setup so absolutely nobody here can do more than guess. Is your MySQL server local or remote? What does your connect string look like in server.cfg? What version of async are you running? To get any help at all, you need to provide details when asking for help.
I am using version 3.00 of mysql async.I will try the latest version 3.2.0
my problem is still not solved 
I’m very sorry to hear it but since you still haven’t answered the rest of my questions, all I can do is wish you the best of luck.
my problem is solved.I just put [libs] as in the picture and took the last version of mysql-async.And no more errors 