Can you update your Joomla backend specific URL at your first post (edit)? Because when i try to access this URL e.g. site.com/administrator it will redirect me to your homepage.

I have temporarily disabled Admin Tools, it should work now. Please let me know when you have finished and I will re-enable it

Hi there,

It seems that i hit error below during maintenance steps.

<br />
<b>Deprecated</b>: Automatically populating $HTTP_RAW_POST_DATA is deprecated and will be removed in a future version. To avoid this warning set 'always_populate_raw_post_data' to '-1' in php.ini and use the php://input stream instead. in <b>Unknown</b> on line <b>0</b><br />
Error displaying the error page: Application Instantiation Error: Failed to start the session because headers have already been sent by "" at line 0.

It would be best if you can consult with your current web hosting service provider regarding this and see how it goes

You have to change 'always_populate_raw_post_data' = '-1' at this file php.ini after that you have to restart your server.

If this problem persist you should upgrade your php version to php 7.0.0 version.
Following are links for your references:-
https://wordpress.org/support/topic/automatically-populating-http_raw_post_data-is-deprecated
https://wordpress.org/support/topic/http_raw_post_data-is-deprecated