Error 18 - Publish Online Failure

When publishing online, InDesign (latest version) is consistently giving error 18 and failing to publish. I've viewed the help center recommendations and have logged out and back in of the Creative Cloud and have changed networks with no success.

In addition, viewing pages through EPUB Interactivity Preview is met with a blank pages.

The ability to publish online is necessary to complete work tasks - a quick resolution would be very appreciated. Thank you.