Maps and Apps Gallery is empty because the token expiring sooner than expected

Description

The token generated for a Maps and Apps Gallery expires sooner than expected. TokenHelper created year-length tokens, but the tokens are expiring in weeks.

Note:
This only affects the 10.1 and 10.1 SP1 releases of Maps and Apps, the version that requires the manual generation and configuration of an ArcGIS.com access token.

Cause

ArcGIS.com no longer generates long-duration tokens; the maximum token duration is two weeks.

Solution or Workaround

If using the version of the Maps and Apps Gallery that requires the token to be configured, it is recommended to convert the site to the latest version. The new version automatically generates the token as needed, which saves the maintenance chore of keeping the token up-to-date.

The latest version is available from Esri's Github site.

Note:
As of April 2018, the Maps and Apps Gallery app template is in the Mature Phase of the ArcGIS Online Product Lifecycle. For more information regarding support of this app template, refer to the Maps and Apps Gallery requirements page.

It is recommended to use the Minimal Gallery app template instead.

There are two important changes to the gallery:

• The proxy.config file now holds the credentials to the ArcGIS.com gallery.
• The configuration file has been converted from JSON to JavaScript; this was done so that it could be run through a validator, which is very helpful for catching typographic errors.

The gallery comes with a web page called checklist.html which is the best way to test and troubleshoot the various aspects of the configuration outside of the application itself.