Sync stuck at 20% for replications in vCloud Director Availability:
Error:
Sync timeout for replication 'C4-8xxxxxxc-5xx1-4xx7-9xx4-4xxxxxxxxx4'.
VMware Cloud Director Availability 4.x.x
vsphere Replication and vsphere Replication NFC services are not enabled on the vmk interfaces of source and destination ESXi hosts for replication traffic.
Please ensure you follow the steps below to achieve resolution:
For more information, Please refer:
Network requirements and prerequisites in the Cloud Director site
In case of NTP issues, follow the document - Troubleshooting VMware cloud director availability NTP Issue