"A general system error occurred: Unable to get signed certificate for host name" when trying to add or reconnect ESXi host to vCenter Server.

Products

• VMware vCenter Server

Issue/Introduction

• Adding or reconnecting ESXi host to the vCenter Server fails with error "rpc_s_too_many_rem_connects"
• The error is also seen when replacing the vCenter certificates.
• vSphere UI error:
  

  Target <Hostname>Status A general system error occurred: Unable to get signed certificate forhost name '<Hostname>' ip '<IP_Address>': Error: Failed to connect to the remote host, reason = rpc_s_too_many_rem_connects

• VPXD log:
  

  YYYY-MM-DDTHH:MM:DDZ info vpxd[7F8557FFF700] [Originator@6876 sub=Default opID=<OP_ID> [VpxLRO] -- ERROR task-####### -- host-##### -- vim.HostSystem.recon
  nect: vmodl.fault.SystemError:
  --> Result:
  --> (vmodl.fault.SystemError) {
  -->  faultCause = (vmodl.MethodFault) null,
  -->  faultMessage = <unset>,
  
  -->  reason = "Unable to get signed certificate forhost name '<Hostname>' ip '<IP_Address>': Error: Failed to connect to the remote host, reason = rpc_s_too_many_rem_connects (0x16c9a046). (382312518)"
  -->  msg = ""
  --> }
  --> Args:
  -->
  --> Arg cnxSpec:
  --> (vim.host.ConnectSpec) {
  -->  hostName = <unset>,
  -->  port = <unset>,
  -->  sslThumbprint = <unset>,
  -->  userName = <unset>,
  -->  password = <unset>,
  -->  vmFolder = <unset>,
  -->  force = false,
  -->  vimAccountName = <unset>,
  -->  vimAccountPassword = <unset>,
  -->  managementIp = <unset>,
  -->  lockdownMode = <unset>,
  -->  hostGateway = (vim.host.GatewaySpec) null
  --> }
  --> Arg reconnectSpec:
  -->

 

Environment

VMware vCenter Server Appliance 6.x
VMware vCenter Server Appliance 7.x

 

Cause

The RPC server is busy due to too many running threads.

Resolution

• Restart the VMCAD service on vCenter to kill the threads:
  service-control --restart vmcad