Check the below steps:
1. You need to create a group for the access on the SZ under Administration --> Admins and Roles --> Click ‘Create’ Under Groups.
2. Create a local user on the "Available Users" step and add it in the "Selected Users".
3. Add the AD under Administration --> Admins and Roles --> AAA --> Create -->.
4. Map the domain name "training.com" (my lab domain name), under "Realm".
5. Enable "Default Role Mapping" and map the SZ User Group create along with along SZ local user created.
6. You need to map the domain and the AD users on the "Windows Domain Name".
7. Example for the domain training.com CN=Users,DC=training,DC=com
8. On the AD, fo to Run >> lpd.exe
9. Click on Connection >> Connect >> type localhost wits port 389.
10. Click on connection >> Bind >> Map the administrator user.
11. Click on View >> Tree >> add the base domain name. In my case it is CN=Users,DC=training,DC=com
Once done, test the authentication from the SZ>> Administration >> Admin and Roles >> AAA >>> Test AAA