Grafana DataSource failed

I created a data source (MySQL) successfully, even added some dashboards.
This start running, and then after about 15 minutes it stopped running and all the data source module failed.

When I open the data source configuration I get this exception
“Error connecting to datasource: dial tcp connect: connection refused”
Even I configure a different ip for MySQL instance. also, the build-in MySQL failed to connect with the same exception.

I’m using Grafana in the cloud (that you created for us). So I have no idea where to find my logs.
And how to restart MySQL data source.
And most important what I did wrong that broke this?

Does your datasource config have the url: Where is your MySQL database located?

No it doesn’t.
Anyway, it being ok now. I didn’t change anything.