Slow site: problem with parser-blocking cross origin script (document.write)?

Hello,

I am trying to debug a rather slow display of my posts and the only error I get is the following: (index):13 A Parser-blocking, cross-origin script, https://ajax.googleapis.com/ajax/libs/jquery/3.0.0/jquery.min.js, is invoked via document.write. This may be blocked by the browser if the device has poor network connectivity. See https://www.chromestatus.com/feature/5718547946799104 for more details.
initJQuery @ (index):13
The site uses Enfold as main theme, integrated with Toolset types. My custom posts display uses a Toolset layout branched to within single.php file in my child Enfold theme.
Even if I empty said layout for test purposes, the page still loads very slowly ( a few seconds).
Any hints?
Thanks.
WP: 4.9 with Enfold 4.0.5
PHP 7.0.25 @64BitOS
512MB memory

• This topic was modified 6 years, 12 months ago by Sim0nb.