pair_failed
What happened
A pairing code works once and expires 10 minutes after it is made. A code that matches no live code is refused with 401, and the reply never says which of the three it was.
What to do
Get a new code from the Engine page in the web app and enter it exactly. The dashes are only there to be read and the case does not matter, but spaces at either end do.
Example
json
{
"error": "That pairing code is wrong, expired, or already used.",
"code": "pair_failed"
}