Have a look at https://nettools.net/howto-troubleshoot-ad-ldaps-connection-issues/ it provides the steps to troubleshoot LDAPS connection issues
Cannot connect to LDAPS on VM
Hello,
We are currently testing with LDAPS and have a Problem with connecting to the LDAP over SSL with the ldp.exe
We have a VM Windows Server 2019 and a Client for testing purposes.
We are able to connect to LDAPS (Port 636) from within our VM-Domain with our VM Client.
But if we try to connect to the LDAPS on 636 with a device from our Azure Domain it does not work
Normal LDAP (Port 389) is working no Problem.
We've tried to get it to work for weeks by this point with different certificates and different approaches to set up the LDAPS
but to no avail...
I suspect that we have to get the Cert onto our Azure Domain and not just the Devices in the Domain but i did not yet find a way how.