Serious Error - Unable to create Amazon advertising campaigns


We’re having some serious problems with our Amazon Advertising Campaigns which are the following:

  •  Unable to add keywords (keyword targeting) and ASINs (product targeting) to any campaigns
  •  Unable to add negative keywords to any campaigns
  •  When creating new campaigns, it shows ‘Incomplete’ and the keywords and negative keywords failed to be added 

We’ve contacted Amazon support multiple times or created multiple cases but all they can tell that the problem is our browsers. We did try different browsers (Chrome, Firefox, Edge, Opera, Safari), reset cached or anything possible but it can’t fix the problem.
Therefore, we strongly believe the problem comes from Amazon system itself. Currently, we have about 5000 campaigns active and this caused us a very big problem.

If anyone has the same problem and know how the way to fix this, we will be appreciated.

Thank you

Here are some images about the problem


What happens if you try to enter a keyword inside the ad group?