This is from FAQ as a trouble shooting but I do not know how to reload the page since the entire Community Builder is not accessible?
I did not see any errors anywhere?
"Sometimes, due to a PHP error, the scripts stop working without displaying an error, leading you to a blank page.
In that case, to find out why, do following:
Check server error logs (not access logs) if you have access to them.
Go to backend, Site, Site Global Configuration, Site Debugging, and turn it on temporarly, then try reloading page, and check page source (HTML source). Don't forget to turn site debug off again.
if it the blank page is outside CB (no "option=com_comprofiler" in URL), e.g. in joomla during installation, add following to the index.php (or index2.php, whichever is in the URL) in frontend or backend where it gives you a blank page, just after the first "<?php" in that file:
ini_set( 'display_errors', true );
error_reporting( E_ALL );
Often, it's due to lack of memory, see other FAQ below.
With the error message, often there is a file which allows you to spot the problem in a component, module, CB plugin or other extension.
Search this forum with a part of error message, sometimes others had same problems, and solutions are posted."
nant