I’m experiencing the same issue reported here (https://wordpress.org/support/topic/metabox-error/) now: “Metabox configuration is required to have an ID parameter”, which makes impossible to create new posts and custom post types.
I have installed PDF Light Viewer Version 1.4.4 and PDF Light Viewer Plugin Pro Version 0.1.5. I’ve noticed the problem is solved by deactivating the PRO version, which means probably the problem is solved in the Light version but it isn’t in the PRO Version.
Could you have a look at it?
Metabox configuration is required to have an ID parameter