I'm following
api.limesurvey.org/classes/remotecontrol..._remind_participants
and sending sessionKey, surveyID, null, null, $tokenIDs
$tokenIDs is an array, for example:
array (
0 => '3881',
)
This is the response I get:
array (
'status' => 'Error: No candidate tokens',
)
The token in question, 3881 was sent an invitation on 17.05.2017
invite_participants and various other methods work fine, so I don't think it's an issue with the session key or survey ID