RuntimeException: No supported encrypter found. The cipher and / or key length are invalid

I started to use Gitlab CI for my Laravel projects, and configured a project (http://ift.tt/1UZtVqE). There is not much test cased but the project setup is ok. I used the same configuration for an another project but the build is failing and shows the following error. The build url is http://ift.tt/1XD1QmB.

RuntimeException: No supported encrypter found. The cipher and / or key length are invalid.

via Chebli Mohamed