i can't assocate associate candidates to job openings through API

i can't assocate associate candidates to job openings through API

Hello,


the return is always the same :
  1. <?xml version="1.0" encoding="UTF-8" ?>
  2. <response uri="/recruit/private/xml/Candidates/associateJobOpening">
  3.     <error>
  4.         <code>null</code>
  5.         <message>null</message>
  6.     </error>
  7. </response>
no error code, no message to help me debug

My API token is Ok because the method   addRecords works

Can you help me please ?