Problem: The login page for Portal for ArcGIS appears blank
When attempting to log in to Portal for ArcGIS, users are sometimes unable to do so because the home page (https://webadaptor.domain.com/arcgis/home/) appears blank.
This issue occurs when an expired esri_auth cookie is supplied by the browser. This is common when the token expiration value is set to a very short time in the ArcGIS REST API.
Solution or Workaround
Below are some recommended options for resolving this issue.
Clear browser cache and cookies
Press Ctrl+Shift+Delete to clear the cache and cookies file in the browser, and reload the page. This allows the esri_auth token to be regenerated. This operation may vary with different browsers.
Increase the token expiration value
The esri_auth token is supplied to the browser to authenticate members. To change the token expiration time and allow the token to be valid for a longer time, refer to the following ArcGIS Help document, Portal for ArcGIS: Specify the default token expiration time.