Our organization is also seeing a similar issue in our environment. Based on our firewall logs, we're seeing client resets whenever vCenter 6.7 attempts to reach IPs 172.66.0.165 & 169.159.140.167 since 13:04 US Central time on Friday, 1/31. We suspect this may be related to Broadcom cutting over from the old VMware sites on that date. This also seemed to drop this vCenter from the domain and we are unable to rejoin it due to an error stating that the Domain is offline, despite being able to reach it from the appliance CLI.