How do I pipe the output of a curl command to an environment variable and use it in another curl command?

I have a REST endpoint that I can get an access token from. To get the access token (JSON web token, JWT) and export that value as an environment variable, I do the following.

export ACCESS_TOKEN=$(curl -i -H 'Content-Type: application/json' -X POST -d @credentials.json http://localhost:8080/api/user/login)

I then echo this token back to the console with echo $ACCESS_TOKEN and get something like this.

 eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiI1MTBlMjRiYWZmZTY0NjMyOGRiNjg1N2ViMTdlZTE1NCIsImFkZHIiOiIwOjA6MDowOjA6MDowOjEiLCJzY2hlbWUiOiJodHRwIiwicG9ydCI6IjgwODAiLCJpYXQiOjE0NjgzNzg5NDV9.COGBYBrx3oQvA2kIiObBOYkEFIL2BODcrSivxWvhuLs-aLsrMGO2z2aCddpwS2yZUB88Q3GOIU8QklbnfRMprQ

Note that there is a space before the first character. I didn't think that was a problem because if I exported the value directly from the console and then echoed it back out, the space is still there.

export ACCESS_TOKEN=eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiI1MTBlMjRiYWZmZTY0NjMyOGRiNjg1N2ViMTdlZTE1NCIsImFkZHIiOiIwOjA6MDowOjA6MDowOjEiLCJzY2hlbWUiOiJodHRwIiwicG9ydCI6IjgwODAiLCJpYXQiOjE0NjgzNzg5NDV9.COGBYBrx3oQvA2kIiObBOYkEFIL2BODcrSivxWvhuLs-aLsrMGO2z2aCddpwS2yZUB88Q3GOIU8QklbnfRMprQ

Now I need to use this token to test my REST endpoints, and tried something like the following.

curl -i \
 -H 'x-access-token: '$ACCESS_TOKEN'' \
 -X POST -d @mydata.json \
 http://localhost:8080/api/data

However, I get the following output.

curl: (7) Couldn't connect to server
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Server
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Access-Control-Allow-Methods
curl: (6) Could not resolve host: POST,
curl: (6) Could not resolve host: PUT,
curl: (6) Could not resolve host: GET,
curl: (6) Could not resolve host: OPTIONS,
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Access-Control-Max-Age
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Access-Control-Allow-Headers
curl: (6) Could not resolve host: Origin,
curl: (6) Could not resolve host: X-Requested-With,
curl: (6) Could not resolve host: Content-Type,
curl: (6) Could not resolve host: Accept,
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Access-Control-Allow-Credentials
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Content-Type
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Content-Length
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: Date
curl: (6) Could not resolve host: Wed,
curl: (7) Could not resolve host: Wed,
curl: (6) Could not resolve host: Jul
curl: (7) Could not resolve host: Jul
curl: (6) Could not resolve host: 03:02
curl: (3) Illegal characters found in URL
curl: (3) Illegal characters found in URL
curl: (6) Could not resolve host: eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiI1MTBlMjRiYWZmZTY0NjMyOGRiNjg1N2ViMTdlZTE1NCIsImFkZHIiOiIwOjA6MDowOjA6MDowOjEiLCJzY2hlbWUiOiJodHRwIiwicG9ydCI6IjgwODAiLCJpYXQiOjE0NjgzNzg5NDV9.COGBYBrx3oQvA2kIiObBOYkEFIL2BODcrSivxWvhuLs-aLsrMGO2z2aCd
HTTP/1.1 100 Continue

HTTP/1.1 403 Forbidden
Server: Apache-Coyote/1.1
Access-Control-Allow-Methods: POST, PUT, GET, OPTIONS, DELETE
Access-Control-Max-Age: 3600
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept, x-access-token
Access-Control-Allow-Credentials: true
Content-Length: 0
Date: Wed, 13 Jul 2016 03:23:04 GMT
Connection: close

If I just directly do export ACCESS_TOKEN=.... in the shell followed by the exact same curl command, then everything works.

Also if I put the export in a sh file, followed by the curl command above then it also works.

#!/bin/bash
export ACCESS_TOKEN=eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiI1MTBlMjRiYWZmZTY0NjMyOGRiNjg1N2ViMTdlZTE1NCIsImFkZHIiOiIwOjA6MDowOjA6MDowOjEiLCJzY2hlbWUiOiJodHRwIiwicG9ydCI6IjgwODAiLCJpYXQiOjE0NjgzNzkwMjB9.lV6jSf9w5_AbsPrNcWcgQpS-DWQVxnH65u06BDGIyL-ST_gg4xXZ2KLAs-kbwckRB3OFy637G1op6PZ2tpHdUQ

Any idea on what I'm doing wrong here?