iControlREST: X-F5-Auth-Token does not exist

If not timeout, then possibly copy & paste (or parsing) error. Run tcpdump to see if your program is sending a correct token.

If not parsing bug, then possibly you didn't get the token at all. Check the response status code and json data.

Try manually first as below.

Get a token:

curl -sk https://mgmtPort/mgmt/shared/authn/login -X POST -H "Content-Type: application/json" \
 -d '{"username":"admin", "password":"secret", "loginProviderName":"tmos"}'

Output (abridged):

{"username":"admin",
 ...
 "token": {
   "token":"3YJFTKX4434X5ZZ7LGBPS5CAVA",
   "name":"3YJFTKX4434X5ZZ7LGBPS5CAVA", 
   ...
 },
 "timeout":1200,       <<< seconds (=20 min)
 "startTime":"2017-07-05T13:42:47.103+1200",
 ...
}

Use the token (let go, Luke):

 curl -sk -H "X-F5-Auth-Token: 3YJFTKX4434X5ZZ7LGBPS5CAVA" \
  https://mgmtPort/mgmt/tm/sys/version

When you've got a wrong token:

 curl -sk -H "X-F5-Auth-Token: 3YJFTKX4434X5ZZ7LGBPS5CA" \ <<< forgot the last two chars.
  https://mgmtPort/mgmt/tm/sys/version

Output

{"code":401,"message":"X-F5-Auth-Token does not xist.", ...}

You can check the available tokens on the system as below:

 curl -sk -H "X-F5-Auth-Token: 3YJFTKX4434X5ZZ7LGBPS5CAVA" \
  https://mgmtPort/mgmt/shared/authz/tokens  | python -m json.tool | grep \"token\"

Output:

            "token": "3YJFTKX4434X5ZZ7LGBPS5CAVA",