Trying to use CRM Web API for on-premises system

Hello all,

currenrtly iam trying to bring the Web API to work. For this purpose i followed this introduction:

https://docs.microsoft.com/en-us/previous-versions/dynamicscrm-2016/developers-guide/mt779074(v=crm.8)

I changed the TODO sections as can be seen in the picture.

If i start the program in the console i need to type my password and after this i got the message: "The request failed with a status of 'Unauthorized'"

I tried with a few account and i can definetely access the CRM with this credentials.

So how can i solve this issue?