Description:
Upon updating to the recent version of Gutenberg, I haven't been able to save or publish posts. I keep getting an "Updating Failed" or "Publishing Failed" error. Tried this on a fresh install of WordPress as well as deactivating all plugins on the site I'm experiencing this on.
To Reproduce
- With Gutenberg installed and updated, create a new post.
- Try to save the new post as a Draft or Publish it.
Expected behavior
I've expected the post to save like it normally does.
Screenshots
Screenshot of post not saving.

Screenshot of the inspector.

Desktop:
- OS: Windows 10
- Browser: Chrome (67.0.3396.99 (Official Build) (64-bit))
Description:
Upon updating to the recent version of Gutenberg, I haven't been able to save or publish posts. I keep getting an "Updating Failed" or "Publishing Failed" error. Tried this on a fresh install of WordPress as well as deactivating all plugins on the site I'm experiencing this on.
To Reproduce
Expected behavior
I've expected the post to save like it normally does.
Screenshots
Screenshot of post not saving.
Screenshot of the inspector.
Desktop: