From this I would deduce that the user object either doesn't exist or doesn't have a `cn` attribute - so the login process crashes when attempting to extract a full name from the user object (which is needed before the account can be created in NAV).
Looks like the problem is a unicode string is being passed to python-ldap:
Traceback (most recent call last): File "/usr/lib/python2.7/dist-packages/django/core/handlers/base.py", line 111, in get_response response = wrapped_callback(request, *callback_args, **callback_kwargs) File "/usr/lib/python2.7/dist-packages/django/views/decorators/debug.py", line 76, in sensitive_post_parameters_wrapper return view(request, *args, **kwargs) File "/usr/lib/python2.7/dist-packages/nav/web/webfront/views.py", line 181, in login return do_login(request) File "/usr/lib/python2.7/dist-packages/django/views/decorators/debug.py", line 36, in sensitive_variables_wrapper return func(*func_args, **func_kwargs) File "/usr/lib/python2.7/dist-packages/nav/web/webfront/views.py", line 216, in do_login account = auth.authenticate(username, password) File "/usr/lib/python2.7/dist-packages/nav/web/auth.py", line 47, in authenticate name=user.get_real_name(), File "/usr/lib/python2.7/dist-packages/nav/web/ldapauth.py", line 272, in get_real_name '(objectClass=*)', [name_attr]) File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 552, in search_s return self.search_ext_s(base,scope,filterstr,attrlist,attrsonly,None,None,timeout=self.timeout) File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 545, in search_ext_s msgid = self.search_ext(base,scope,filterstr,attrlist,attrsonly,serverctrls,clientctrls,timeout,sizelimit) File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 541, in search_ext timeout,sizelimit, File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 99, in _ldap_call result = func(*args,**kwargs) TypeError: ('expected string in list', u'cn')