Cannot establish a TCP connection to server at 'xx.xx.xx.xx:443'.

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• A newly added ESXi host with Version 8.0U2 and above or a host upgraded to 8.0U2 and above displays this error in the SRM UI:

Error : Cannot establish a TCP connection to server at 'xx.xx.xx.xx:443'.

• There is no connectivity issue between the vSphere replication appliance and the ESXi host..
• It appears disconnected in the SRM UI under  replicated servers list along with the vSphere replication management server and add-on vSphere replication appliances:

 

Environment

VMware vSphere Replication 8.x

VMware vSphere Replication 9.x

Cause

• This is an expected behavior because the host is put in maintenance mode which closes connection over port 443 on the ESXi for hbrsrvuw service.

• In /var/log/envoy.log file of the ESXi connection closed on port 443 is logged .

2025-05-09T08:05:19.461Z In(166) envoy[2098962]: "2025-05-09T08:05:16.105Z warning envoy[2099295] [Originator@6876 sub=filter] [Tags: "ConnectionId":"187523"] closing connection SSL<127.0.0.1:33176, 127.0.0.1:443>"

Resolution

Taking the host out of maintenance mode will ensure connection over port 443 is opened on the ESXi for hbrsrvuw service to communicate with the vsphere replication appliance.