Contact your hosts server admin.

I did that first and they advised its Concrete5 is the problem...

What is the complete error message, or is that all you see?
What is your website address?

Warning 210.79.53.53 mod_fcgid: stderr: PHP Warning: require_once(/var/www/vhosts/merje.co.nz/httpdocs/updates/concrete5.6.3.5_remote_updater/concrete/core/libraries/object.php): failed to open stream: No such file or directory in /var/www/vhosts/merje.co.nz/httpdocs/updates/concrete5.6.3.5_remote_updater/concrete/startup/required.php on line 4 Apache error

Warning 210.79.53.53 mod_fcgid: stderr: PHP Fatal error: require_once(): Failed opening required '/var/www/vhosts/merje.co.nz/httpdocs/updates/concrete5.6.3.5_remote_updater/concrete/core/libraries/object.php' (include_path='/var/www/vhosts/merje.co.nz/httpdocs/libraries/3rdparty:/var/www/vhosts/merje.co.nz/httpdocs/updates/concrete5.6.3.5_remote_updater/concrete/libraries/3rdparty:.:/usr/share/pear') in /var/www/vhosts/merje.co.nz/httpdocs/updates/concrete5.6.3.5_remote_updater/concrete/startup/required.php on line 4

Site ishttp://www.merje.co.nz and merjeddm.co.nz

That error message is saying that there is a file (object.php) or a folder (libraries) missing from your system.
If you have a file manager in your hosts control panel, take a look for the folder and file in updates/concrete5.6.3.5_remote_updater/concrete/core/libraries/object.php.

If the file or the folder do not exist, I have attached both the individual file and the folder as zip files for you.

If you want me to take a look for you, send me the login details for the server by Private Message.
I will need the control panel web address, the username and the password.
Incidentally your server is returning a HTTP ERROR 500 for both of your domains which would indicate a server error rather than a concrete5 error...