I installed a fresh Wordpress 4.9.8 on your System using the commandline tool: WP-CLI.
Everything seams to work fine in the frontend. But in the backend I get the following error on the Dashboard:
Uncaught TypeError: a.widget is not a function
When using the Customizer I get even more Errors:
Uncaught ReferenceError: jQuery is not defined
In addition to this I don't see the Icons on the Admin Dashboard. But when I want to create or edit a Post everything is fine.
I know that this looks like a typical: U got your jQuery not added right thing. But it's a fresh clearn Wordpress 4.9.8 without any customisation. How can there be those errors?
Hopefully somebody can help me with this, cause I don't want to start messing with it unless it works properly.