AWS MGN: Data replication stalled

We have installed agent in virtual machine successfully but getting error error is- Data replication stalled Failed to launch Replication Server. We already allowed the port 443 and 1500 to local windows firewall and their existing pfsense. Can someone explain why I get this error and where I can look to correct it? The "How can I solve this?" takes you to general troubleshooting and none of the troubleshooting topics have this error.. Thank you! Enter image description here