The most likely cause for the failure in joining the Active Directory domain when setting up Nutanix Files, given the error message about the inability to connect to logon servers and valid credentials, points to network communication issues. The specific mention of "ads_connect: No logon servers" suggests that the File Server VMs (FSVMs) are unable to reach the domain controllers. This issue is often due to necessary network firewall ports not being open. Ensuring that all required ports for Active Directory communications are open between the FSVMs and the domain controllers would resolve this issue.References: Nutanix Files Administration Guide, Active Directory Services Network Configuration requirements.