The application is not valid when plugin activated.

Hello,

Whenever I try to activate this plugin after deploying to the app engine I get a blank admin page and my admin logs give me this stack trace:

PHP Fatal error:  Uncaught exception 'google\appengine\api\app_identity\AppIdentityException' with message 'The application is not valid.' in /base/data/home/runtimes/php/sdk/google/appengine/api/app_identity/AppIdentityService.php:285
Stack trace:
#0 /base/data/home/runtimes/php/sdk/google/appengine/api/app_identity/AppIdentityService.php(83): google\appengine\api\app_identity\AppIdentityService::applicationErrorToException(Object(google\appengine\runtime\ApplicationError))

Only the admin page is blank. The rest of the site is accessible and works.

https://www.ads-software.com/plugins/google-app-engine/