One of my customers had a problem with his Edge subscription, resulting in the following error:
Failed to connect to the Edge Transport server ADAM instance with exception The LDAP server is unavailable.. This could be caused by a failure to resolve the Edge Transport server name <Edge_FQDN> in DNS, a failure trying to connect to port 50636 on <Edge_FQDN>, network connectivity issues, an invalid certificate, or an expired subscription. Verify your network and server configuration.
The obvious troubleshooting steps are to check firewall ports 50389 and 50636 (using a telnet client) and DNS resolution in both directions.
If both of them are ok, run Start-EdgeSynchronization. If it shows the same error, the solution is to delete and recreate the Edge subscription:
- On one of your mailbox servers, run Get-EdgeSubscription | Remove-EdgeSubscription
- On the Edge, run New-EdgeSubscription -FileName C:\temp\edge.xml. Repeat on other Edge servers if needed.
- Copy the exported files to one of your Mailbox servers
- On that Mailbox server, run New-EdgeSubscription -FileData ([byte]$(Get-Content -Path “C:\temp\edge.xml” -Encoding Byte -ReadCount 0)) -Site “<sitename>” => the name of the site can be found in Active Directory Sites and Services.
- Run Start-EdgeSynchronization
- If this still fails, it might be needed to restart the AD LDS service (and all dependent services) on the Edge servers.
- To verify replication, run Test-EdgeSynchronization and make sure it works.