Fetch DN

It's not the DN (syntax).

The FGT cannot contact the LDAP server. IMHO a secure LDAP connection (LDAPS) uses port 636, not 389.

Either switch back to regular LDAP or check the secure connection (username, password, protocol).

Hello,

Login to your Windows Domain Controller and type into the CLI:

C:\>dsquery user -samid administrator

You will get something like this:

C:\>dsquery user -samid administrator "CN=Administrator,CN=Users,DC=homelab,DC=local"

Put the CN=Administrator,CN=Users,DC=homelab,DC=local into the User DN field (Bind type: Regular).

Set the admin password.

Use sAMAccountName as Common Name Identifier.

Use dc=homelab,dc=local as the Distinguished Name. (The CN=User means a group in the homlab.local domain, so in this case only the domain was used. Set the domain at first to see whether the LDAP will work. You can set an OU or CN later on to what you need to not search the whole LDAP tree. It depends what you need.)

Try the Test without the Secure Connection. It should work. If you will use the Securte Connection you will need probably some certificate issued by your CA in the Windows AD environment - Someone else can correct me if I am wrong.