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

Question

I am building a project using Laravel. It was working fine on localhost, but when I upload it to the server (the server has comodo ssl installed), I receive the following er

Answer 1

I was suffering with this problem for a few too many hours before I discovered that the key was being cached in the bootstrap\cache\config.php. Deleted the file and my site loaded fine (i.e. there was otherwise no problem with my config).

I discovered this by adding some debug output to boostrap\cache\compiled.php to make it spit out the cipher and key (somewhere around line 7010). Then dug around to see how it was picking up the config and found it uses a cache config file.