I published a new report recently, but it couldn't show on the PowerBI Service Workspace and gave me a warning message as below. However, the same data source is used for my other reports as well, which has no issue with showing at all.
When you publish a report to Service , it will automatically generate a dataset in Service as well as the report you uploaded . If you didn't import your data to create report , you need to configure gateway to make sure the data is transferred so you can see the data in Service.
Add or remove a gateway data source - Power BI | Microsoft Learn
Community Support Team _ Ailsa Tao