GitLab.com runner postgres connection not possible

I did setup for my app gitlab.com project and used shared runner, for DB I use postgres and I have in my gitlab-tasks this connection, this worked fine for me in last 6 months, but now all the time the connection fails, the error is following:

SQLSTATE[08006] [7] could not translate host name "postgres" to address: Na  
   me or service not known

I already tried to define other hostname like localhost or 127.0.0.1 but it’s the same… Does anybody has a idea what could be wrong here?