Installation Error – 500 Server Error On Installation

We have heard of this issue before with 1&1. You need to contact them and advise them that this is an issue with the version of PHP running on your server.

Ask them to ensure that you are running the latest version of PHP on your server, and also advise them to add the follow line in the .htaccess file, best in the root directory.

AddHandler x-mapp-php5 .php