407 authenticationrequired In jmeter

I work in a company where we use a proxy to access any browser website.

We would like to start API testing with Jmeter, but have on problem.

Whenever i try to ad an Api call to petstore.swagger.io/v2/pet/10 for example and put in the proxy details in the "advanced" section of the http request + adding an http authorization manager with Username + Password it still gives me an 407 error back Authenticationrequired.

Request header : Request header

Response header : Response header

In the information i have also it's that the proxy is " Ruleset Name: Authentication with Kerberos and NTLM Fallback"

This is quite a problem if i'd like to test internal API's with any authorization on it.

Any help is greatly appreciated.

Best regards.