How to resolve error For the response: use 'Content-Type' header"

I'm using Design Center to specify my API and have to add some Rule Sets. One on them is API Team Best Practices and indicates the follow error:

Error: [API Team Best Practices] For the response use 'content-Type' header .

My code follow like this:

Design Center Image

Then I Add the content Header , like this

After fix the error

But The Rule set still error me , calling the following message:

**

1. Parameters of type string must have the format field declared.

**

what am i missing? Any help ? Thanks

Use this article as reference of my problem https://help.mulesoft.com/s/article/Error-Error-Anypoint-Best-Practices-For-the-response-use-Content-Type-header-occurs-wen-designing-an-API-Specs-in-Design-Center-based-on-Anypoint-API-governance-Best-Practices