Have you refreshed the dataset after 24-48 hours according to its requirements?
If there are any issues with the dataset refresh/app update during the updating process, please validate the following steps and refresh the dataset.
Follow the steps below to make sure your dataset configurations are set correctly:
Go to the workspace panel and open the app workspace.
Open the Scheduled Refresh option in the dataset settings.
Open the Parameters section and configure the data source once again in the Data Source section with the credentials with which you have access to the Tenant ID with valid permissions, mentioned in the prerequisites section above.
Once the above steps are validated, go back to the app workspace and click on the Refresh option.
Once the dataset has refreshed successfully, click the Update App option at the top-right corner of the app workspace.
Based on the above information, if you are a Power BI Pro licensee, you can create a support ticket for free and a dedicated Microsoft engineer will come to solve the problem for you. It would be great if you continue to share in this issue to help others with similar problems after you know the root cause or solution.
Thanks for your sharing !
"I think the reason for the problem is new tenant won't have data before June, because we changed the Office365 tenant in July."