Get auth keys returns 404 or 401 - unautherized

[Daniel Setréus]

Hi

I'm trying to request auth keys from change API. This is what I POST:

'api_key' => $this->petApi, 

'source_description' => 'Petition published at ' . bloginfo('name'),

'source' => home_url() . '/' . $this->petId,

'requester_email' => get_option('admin_email'),

'callback_endpoint' => plugin_dir_url( __FILE__ ) . '/getAuthKeys.php',

'timestamp' => date('c')

I'm posting it to https://api.change.org/v1/petitions/'. $this->petId .'/auth_keys

First I got a 401 response - but after trying a couple of times, not changing anything in the post adress, I now get a 404 (not found) response... 

Can any one help? Thank you in advance.