Error 401 when accessing the REST API with token

I'm trying to integrate my code repository and my TeamCity Server, to make each commit trigger a build. I tried to access TeamCity Server through URL, but  I keep getting access denied related errors.

Here are some information I'm using:

Request URL: https://myteamcity:port/httpAuth/app/rest/builds

X-Auth-Token: mytoken

Response body: Incorrect username or password. To login manually go to "/login.html" page

PS: mytoken is generated on My Settings & Tools | Access Tokens.

What am I doing wrong?

Appreciate any help on this.