Here you can find information regarding different scenarios you may face when refreshing data within the Power BI service.
If you have a web connector script that's using the Web.Page function, and you have updated your dataset or report after November 18th, 2016, you need to use a gateway in order for refresh to work properly.
When configuring a dataset, you may get an error indicating the dataset uses an unsupported data source for refresh. For details, see Troubleshooting unsupported data source for refresh
Please wait about 10-15 minutes for refresh to be reflected in the dashboard tiles. If it is still not showing up, re-pin the visualization to the dashboard.
You may encounter GatewayNotReachable when trying to set credentials for a data source. This could be the result of an outdated gateway. Install the latest gateway and try again.
This could be an issue with your M script within your Power BI Desktop file or Excel Workbook. It could also be due to an out of date Power BI Desktop version.
For a list of errors you may encounter with dashboard tiles, and explanations, see Troubleshooting tile errors.
The Azure Active Director (AAD) OAuth token, used by many different data sources, expires in approximately one hour. You can run into situations where loading data takes longer than the token expiration (more than one hour), since the Power BI service waits for up to two hours when loading data. In that situation, the data loading process can fail with a credentials error.
Data sources that use AAD OAuth include Microsoft Dynamics CRM Online, SharePoint Online (SPO), and others. If you’re connecting to such data sources, and get a credentials failure when loading data takes more than an hour, this may be the reason.
Microsoft is investigating a solution that allows the data loading process to refresh the token and continue. However, if your Dynamics CRM Online or SharePoint Online instance (or other AAD OAuth data source) is so large that it could run into the two-hour data-load threshold, you may experience a data load timeout from the Power BI service as well.