Property error when posting news from template

Added 3 columns to the page library.
Category / Choice
Important / Yes No
Outgoing department / choice

When creating a page template, selecting a property results in the following error:
Unable to get page details. It could be a connectivity issue or some other issue. Please refresh the page and try again.

What can I do to solve this problem?

Postscript
There were 400 errors in the console log when the browser developer tools encountered an error.