Burp Collaborator is a great feature in Burp Suite Pro that helps discover a broader attack vectors. However, sometimes I came to a situation where injecting cookies by burp collaborator affects the authentication and makes the application return authetnication failure even with correct credentials.

Anyway, regardless of the reason of why you may need to disable burp collaborator, here is the how

  1. Go to Project options tab.
  2. Under Project options tab, Go to Misc tab.
  3. Scroll-down to Burp Collaborator Server
  4. Select Don't use Burp Collaborator