.. _troubleotpauth:

OTP Authentication
------------------
If OTP authentication fails for a user you might check the following:

 * Verify that the tokens for this user are not locked.
 * Verify that the fail counters of the tokens of the user have not reached the max fail count.
 * Try to authenticate via the LinOTP Web API. This will give you a better idea of the error and rule out error 
   source like the RADIUS server or the PAM module. For doing this use a web browser and go to the URL::

	https://<yourlinotpserver>/validate/check?user=<login>&pass=<OTPPINOTPvalue>.

 * The return will be a JSON structure. Either download it and view it with your preferred text viewer or get the
   `JSONViewer Plugin <https://addons.mozilla.org/de/firefox/addon/jsonview/>`_ for your browser.
 * Take a look at the log file on the LinOTP server. Probably it is the file: ``/var/log/linotp/linotp.log``.
 * Take a look at the RADIUS server log file.