"Unable to authenticate user", System Configuration tab fails to load on vCenter Server Appliance 6.7

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Selecting System Configuration Tab under Administration from HTML 5 Client (vsphere-ui) loads and empty page
• In log file /var/log/vmware/vsphere-ui/vsphere_client_virgo.log, you see entries similar to : 

[2020-03-06T11:28:13.149-05:00] [ERROR] cm-service-thread-pool-230   70000199 100005 200002 com.vmware.vsphere.client.cm.util.ServerPropertyValueE
xtractor    com.vmware.vapi.std.errors.Unauthenticated: Unauthenticated (com.vmware.vapi.std.errors.unauthenticated) => {
    messages = [LocalizableMessage (com.vmware.vapi.std.localizable_message) => {
    id = vapi.security.authentication.invalid,
    defaultMessage = Unable to authenticate user,
    args = []
}],
    data = <null>
} java.lang.RuntimeException: com.vmware.vapi.std.errors.Unauthenticated: Unauthenticated (com.vmware.vapi.std.errors.unauthenticated) => {
    messages = [LocalizableMessage (com.vmware.vapi.std.localizable_message) => {
    id = vapi.security.authentication.invalid,
    defaultMessage = Unable to authenticate user,
    args = []
}],
    data = <null>

• In log file, /var/log/vmware/applmgmt/applmgmt.log, you see entries similar to :

2020-03-06T16:00:13.137 [21262]ERROR:vmware.appliance.extensions.authentication.authentication_sso:Unhandled exception during SAML token validation
Traceback (most recent call last):
  File "/usr/lib/python3.5/urllib/request.py", line 1254, in do_open
    h.request(req.get_method(), req.selector, req.data, headers)
  File "/usr/lib/python3.5/http/client.py", line 1107, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib/python3.5/http/client.py", line 1152, in _send_request
    self.endheaders(body)
  File "/usr/lib/python3.5/http/client.py", line 1103, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python3.5/http/client.py", line 934, in _send_output
    self.send(msg)
  File "/usr/lib/python3.5/http/client.py", line 877, in send
    self.connect()
  File "/usr/lib/python3.5/http/client.py", line 1261, in connect
    server_hostname=server_hostname)
  File "/usr/lib/python3.5/ssl.py", line 385, in wrap_socket
    _context=self)
  File "/usr/lib/python3.5/ssl.py", line 760, in __init__
    self.do_handshake()
  File "/usr/lib/python3.5/ssl.py", line 996, in do_handshake
    self._sslobj.do_handshake()
  File "/usr/lib/python3.5/ssl.py", line 641, in do_handshake
    self._sslobj.do_handshake()
socket.timeout: _ssl.c:703: The handshake operation timed out

Note:The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.

Environment

VMware vCenter Server Appliance 6.7.x

Cause

This issue is observed in environments with Proxy configured on vCenter Server Appliance and the connection to authenticate user fails while going through proxy.

Resolution

• Connect to the VAMI Page of vCenter Server Appliance (https://vcsa_fqdn:5480)
• Remove the Proxy Configuration, refer to Configure the DNS, IP Address, and Proxy Settings to navigate to the Proxy Configuration Page
• Reboot the vCenter Server Appliance
• Retry loading System Configuration Tab