Page management - Generic error is shown when user attempts to create a page with a name that already exists

1. Login as admin/editor
2. Navigate to Channel manager >> my project >> edit channel >> pages
3. Click on add new page
4. In page title add "about" (this already exists)
5. Click on create page

Expected - Error saying that about page already exists and user is not allowed to navigate away
Actual - A generic error is shown "A technical error has occurred" (refer screenshot)