Mandraled Hosting operates multiple PHP versions. When executing commands like Composer via SSH, the system defaults to a basic PHP version used for internal tools. To access a fully-featured PHP installation, users must specify the complete path to their desired PHP version.
Solution
The command requires specifying the PHP version explicitly. For example, using PHP 7.1:
/usr/bin/php71 -f /usr/bin/composer
A complete installation command would look like:
/usr/bin/php71 -f /usr/bin/composer install
Additional Information: Upon SSH login, users receive a message of the day (MOTD) that displays all available PHP versions on their server.