This time very short and quick post:) If you see such error message (as below) in vCenter when adding or replacing VMware vSAN 6.7 Witness Appliance, just remember:

CHECK YOUR vSAN Witness Appliance VERSION AND BUILD.
The witness host must be capable of running the same version of ESXi as vSAN data nodes.

2019-11-08T18:24:31.613Z info vsand[2100317] [opID=Thread-2 VsanHealthDaemon::doVsanHealthCheck] Skip VSAN health check due to the VSAN is disabled
2019-11-08T18:24:35.534Z info vsand[2100316] [opID=Thread-1 VsanPyVmomiProfiler::logProfile] invoke-method:ServiceInstance:RetrieveContent: 0.01s, consumed: 66052KB (+0KB), consumedPeak: 67820KB (+0KB), effectiveMin: 102400KB (+0KB), effectiveMinPeak: 102400KB (+0KB), requestedMinPeak: 102400KB (+0KB)
2019-11-08T18:24:35.554Z info vsand[2100316] [opID=Thread-1 VsanMgmtUtil::init] Initialized ObjectCache: ‘healthSummaryCache’, maxSize=1024, ttl=None
2019-11-08T18:24:35.556Z info vsand[2100316] [opID=Thread-1 VsanMgmtUtil::init] Initialized ObjectCache: ‘healthHistoricalCache’, maxSize=1024, ttl=4000
2019-11-08T18:24:35.557Z info vsand[2100316] [opID=Thread-1 VsanVcPerformanceManagerImpl::init] VsanVcPerformanceManagerImpl init
2019-11-08T18:24:35.557Z verbose vsand[2100316] [opID=Thread-1 VsanVcDiskFormatConverterImpl::Reinit] Vsan Upgrade System init
2019-11-08T18:24:35.560Z info vsand[2100316] [opID=Thread-1 VsanVcObjectSystemImpl::init] VsanVcObjectSystemImpl init
2019-11-08T18:24:35.560Z info vsand[2100316] [opID=Thread-1 VsanResourceCheckSystemImpl::init] VsanResourceCheckSystemImpl init
2019-11-08T18:24:35.561Z info vsand[2100316] [opID=Thread-1 VsanMgmtUtil::init] Initialized ObjectCache: ‘DiskMappingCache’, maxSize=2000, ttl=None
2019-11-08T18:24:35.561Z info vsand[2100316] [opID=Thread-1 VsanVcIscsiTargetSystemImpl::init] VsanVcIscsiTargetSystemImpl init
2019-11-08T18:24:35.909Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:24:35.909Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:24:40.913Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:24:40.913Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:24:45.915Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:24:45.915Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:24:50.919Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:24:50.919Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:24:55.923Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:24:55.923Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:25:00.925Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:25:00.925Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:25:05.929Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:25:05.930Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:25:10.931Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:25:10.931Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)
2019-11-08T18:25:15.934Z error vsand[2100281] [opID=MainThread cliutils::GetVSANClusterInfo] Failed to query cluster info: Operation not allowed because the VMKernel is shutting down
2019-11-08T18:25:15.935Z verbose vsand[2100281] [opID=MainThread statsdaemon::HandleRoleChanges] detecting role transition… (newRole = agent, oldRole = agent)