I think you have Alert rules that are attached to a panel. The query of an alert rule almost always matches the query of the panel unless someone changes one but not another.
Grafana evaluates those rules regularly, and when the query does not return any data, the default behavior is to send a special alert DatasourceNoData.
If you want to stop getting these alerts but keep evaluating rules, then update every rule and change how to treat no-data situations. Learn more Separate alert-rules instead of instances of one alert rule?