Hello Peter,
I am suspecting that you haven’t meet the minimum requirements to run WordPress. Please ensure that you have at least PHP 7.0 version in your server. For the rest of the requirements, please check this out: https://wordpress.org/about/requirements/
And we also recommend that you increase your memory allocated to PHP. To increase it, please edit your wp-config.php file and insert these lines:
define( 'WP_MEMORY_LIMIT', '256M' );
define( 'WP_MAX_MEMORY_LIMIT', '512M' );
You can add it before the line
/*That's all, stop editing! Happy Blogging. */
We would loved to know if this has work for you. Thank you.