Problem with API Call. PLS HELP

Hello, I got a Problem. I want to make a API Call to Now the problem is, the API Key is in the headers of the call. -> “Ocp-Apim-Subscribtion-Key”. But when I make a Call I get the error: "“statusCode”: 401, “message”: “Access denied due to invalid subscription key. Make sure to provide a valid key for an active subscription.” And this doesnt make sense to me because I have the subscribtion Key in the headers of the API Call. Please Help.