No groups have been found for this user - adirectory/ldap

Question

I know that I have tried this test before and it worked, but every time I test user authentication under Definitions and Users > Authentication Services > Servers, I get "Denied - No groups have been found for this user". 
 The UTM has been in use for over a year and we are not having any authentication issues, but in adding an LDAP server for UPN authentication, the test always fails. I went back and tested the adirectory servers that were already created and got the same result. I have tried every permutation of user name that I can think of: 
 domain\user.name 
 user.name@domain.com 
 "User Name" 
 CN=user.name 
 I got to be missing something simple, the server test itself works fine. Just the user test fails.

Richard Hawkins · Answer

Check your prefetch setting to sync AD. Definitions & Users>Authentication Services>Advanced. The minimum period you can set the UTM to sync with AD is once every 24 hours. You can manually sync with AD and that will correct this.