@HussainMohammed,
Another thing to check outside of what @Astardzhiev mentioned is that you aren't dropping the LDAPS traffic on the firewall itself if your management interface traffic has to route through security zones. The firewall will see LDAPS traffic as standard SSL traffic, so you'll either need to create an application-override entry, a custom app-id, or just allow ssl over 636/tcp in your security rulebase.
I've seen a lot of people spend a lot of time troubleshooting LDAPS issues without verifying that the traffic is actually getting allowed.
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