ShibbolethAuthLimeSurvey plugin authentication is not working correctly

[mberva]

Hi,

I installed the ShibbolethAuthLimeSurvey plugin but after successfully requesting and entering the credentials (our idp interface), limesurvey asks again for authentication showing the Authdb interface

the apache conf is:
<Location /limesurveyDEV>
AuthType shibboleth
ShibRequireSession On
require valid-user

ShibbolethAuthLimeSurvey setting is:
Shibboleth attribute of User ID = eduPersonPrincipalName
Shibboleth attribute of User first name = givenName
Shibboleth attribute of User surname = sn
Shibboleth attribute of User email address = mail

What am I doing wrong?

Thank you in advance!