Play Framework deploy failed: "the application secret has not been set, and we are in prod mode. Your application is not secure"

Question

I'm deploying on Heroku a web application developed with Play Framework. The deploy fails returning this error:

[error] p.a.l.c.CryptoConfigParser - The application secret has not been set, and we are in prod mode. Your application is not secure. 

What does it means that "we are in prod mode"? Where do I set the mode? I have to change this because it's not a production environment.

Thanks

Answer 1

Put this into your conf/application.conf

Play 2.5

play.crypto.secret="changethissosomethingsecret"

Play 2.6+

play.http.secret.key="changethissosomethingsecret"

You can also start your application with a source with a secret key as a parameter.