Pipeline MySQL service no longer work

I run pipeline for my project two months ago and everything OK but today it not working. I can't connect to MySQL service (through code). I didn't change any code before.

Note: I try to use command netstat -nplt and see just only redis port is listening, no mysql port.

Please check this function, and if it not a bug, please tell me what can I do to fix the problem.

Thank you.