Frontend Server testweise mit Zertifikat von Let’s Encrypt versorgt – ab da Events mit Source LS File Transfer Agent Service und ID 1017:

File transfer failed for some replica machines. Skype for Business Server 2015, File Transfer Agent will continuously attempt to replicate to these machines.

While this condition persists, configuration changes will not be delivered to these replica machines.
Replica file transfer failures: edgeserver.meinedomäne.com: Https request failed.

Details: System.ServiceModel.FaultException: Invalid certificate presented by remote source in cluster frontendserver.meinedomäne.com. Details: No match.

In Anlehnung an diesen Artikel das Zertifikat der Let’s Encrypt Intermediate CA in den Computer Store, Folder “Intermediate Certification Authorities” importiert, SfB Services restarted und Ruhe kehrt ein.