Error: We failed to download the app asset file from ...

Overview

Some applications running on OpenFin require additional Assets to provide functionality.  The asset is hosted on a remote server, where the assets have been declared in the application manifest the OpenFin Runtime Version manager will attempt to download the asset upon application launch.

An application may fail to start if an asset is defined as mandatory and the Runtime Version Manager is unable to download the asset to the local machine.

Potential Causes: 

• The 'Assets URL' is invalid
• The server hosting the Asset is unavailable
• The network path to the server hosting the Runtime is not open

Troubleshooting steps:

1. Copy the full assets URL from the error and paste it into a Web Browser, this should initiate a file download.  If the file download works in a browser, compare the Browsers network configuration with the local systems default settings. 
2. If the download fails in the step above:
   1. Check with the local network team that the network path to the URL is open
   2. Check with the application provider that the URL is correct, and the server is operational
3. Check the network.log file, located in %LocalAppData%\openfin\logs for errors that have been returned by the network stack.  You should be able to find the request for the runtime:

   [1234:12345] We failed to download the app asset file from ....

   In the lines preceding this error you may find Network-specific errors including TCP or HTTP codes that can be used to determine the reason why the file failed to download.