Blogs visible but categories not working

Hi

Whilst we are still able to view our posts (blogs), when I try to open the link to access post categories, it returns a critical error.

I have disabled all plugins that could have potentially caused the issue and have rolled back to best known date.

Any idea why this might be happening, and more importantly, steps I can take to fix this.

• This topic was modified 6 minutes ago by nick7697.

The page I need help with: [log in to see the link]