RESTAPI - Send HTTPS request

Hello, 

I am sending HTTPS request using REST, Web project which requires username and password. But unable to get the expected response. Below is the info.

Request: GET,

URL: https://abc.xyz.com/api/info/version

I am not sure where to enter or where is the field for Username and Password so, I selected 'Authorization' from Headers and entered value (Value is basic Base64). 

After sending request, I get attached response. 

I added the cert in my trusted root but no luck. 

Can you please help with it? What am I doing wrong or am I missing something?

Thanks, 

Ashish Thakkar