Adding CriterionUserInterest to Campaign always returns CriterionError.CANNOT_ADD_CRITERIA_TYPE

[Tal Ater]

I'm trying to add a negative User Interest Criterion to one of my 
campaigns, but I keep getting the same error from the API:

[CriterionError.CANNOT_ADD_CRITERIA_TYPE @ operations[1].operand.criterion; 
> trigger:'USER_INTEREST', CriterionError.CANNOT_ADD_CRITERIA_TYPE @ 
> operations[2].operand.criterion; trigger:'USER_INTEREST']
>

This is the code I am using:

          $interestId = 736; //Linux & Unix
          $interest = new CriterionUserInterest();
          $interest->id = $interestId;
          $campaignCriterion = new NegativeCampaignCriterion();
          $campaignCriterion->campaignId = 1234567;
          $campaignCriterion->criterion = $interest;
          $operations[] = new 
GoogleApiAdsAdWords_CampaignCriterionOperation($campaignCriterion, 'ADD');
          $campaignCriterionService->mutate($operations);

Any ideas?

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