If you have been having problems with Edge browser loading data, I finally found a fix. It works, but it is not a practical long-term solution. This is mostly for users of phones running Windows 10 Mobile.
Use an InPrivate browser tab.
This works for most apps so far. Apps that load from OneDrive still have problems.
Use a regular tab.
... > Settings > Clear browsing data > Choose what to clear > Cached data and files > Clear
You might have to do this every time you update your app.