Symptoms:
20##-##-##T##:14:57.469Z info vpxd[7F##########] [Originator@#### sub=InvtHostCnx opID=AddHostWizard-add-68####-ngc-15] [VpxdInvtHostCnx] SSLVerifyException: Untrusted certificate found on host <esxihostname> Pushing new certificate...20##-##-##T##:14:57.504Z info vpxd[7F##########] [Originator@#### sub=vpxLro opID=dam-auto-generated: GenerationNumbersMonitor:dr-##:##-##] [VpxLRO] -- BEGIN lro-1375#### -- ResourceModel -- cis.data.provider.ResourceModel.query -- 52b 20##-##-##T##:14:58.218Z info vpxd[7F##########] [Originator@#### sub=Vsan opID=AddHostWizard-add-68####-ngc-15] Destroying VSAN dynamic MOs for host-ID.20##-##-##T##:14:58.220Z info vpxd[7F##########] [Originator@#### sub=licenseClient opID=AddHostWizard-add-682626-ngc-15-LicenseClientUnregisterHostAsync-41312d8c] Unregister host: 'host-ID'20##-##-##T##:14:58.251Z info vpxd[7F##########] [Originator@#### sub=vpxLro opID=AddHostWizard-add-68####-ngc-15] [VpxLRO] -- FINISH task-29####20##-##-##T##:14:58.251Z info vpxd[7F##########] [Originator@#### sub=Default opID=AddHostWizard-add-68####-ngc-15] [VpxLRO] -- ERROR task-29#### -- group-h4-- vim.Folder.addStandaloneHost: vmodl.fault.SystemError:--> Result:--> (vmodl.fault.SystemError) {--> faultCause = (vmodl.MethodFault) null,--> faultMessage = <unset>,--> reason = "Unable to get signed certificate forhost name 'esxihostname' ip '###': Error: Operation failed with error = ERROR_ACCESS_DENIED (5) (5)"--> msg = ""20##-##-##T##:##:##.161380+00:00 info vmcad t@14063: Checking upn: cn=CAAdmins,cn=Builtin,dc=vsphere,dc=local against CA admin group:groupname@vsphe20##.##c##
20##-##-##T##:##:##.161832+00:00 info vmcad t@140635667420928: Checking user's group: cn=DCClients,cn=Builtin,dc=vsphere,dc=local against CA admin group: cn=CAAdmins,cn=Builtin,dc=vsphere,dc=local20##-##-##T##:##:##.162232+00:00 warning vmcad t@140635667420928: error code: 0x0000000520##-##-##T##:##:##.162680+00:00 warning vmcad t@140635667420928: error code: 0x0000000520##-##-##T##:##:##.163033+00:00 warning vmcad t@140635667420928: error code: 0x00000005
The user this was attempted with was not a member of CAAdmins.
First option is to change vpxd.certmgmt.mode from vmca to thumprint to add ESXi host.
If that doesn't help, add DCAdmins , DCClients and waiter- under CAAdmins SSO group .
These are created by default during installation or upgrade and add ESXi to VC with the vpxd.certmgmt.mode in vmca.