Problem
You have a Citrix Virtual Apps and Desktops environment hosted with Citrix Cloud Connectors connecting to Citrix cloud and noticed that the management portal displays virtual machines in a machine catalog with the Power State as Unknown:
This appears to only affect machines hosted by a specific vCenter because virtual desktops hosted on a different vCenter displays the Power State properly. Monitoring the VDIs also indicate that users are not able to connect to them.
Solution
A quick search on the internet will only return the following Citrix KB that refers to an on-premise deployment without Citrix Cloud connectors:
VM’s Power State Does Not Update And Shows As “Unknown” After vCenter Server Reboots
https://support.citrix.com/article/CTX238157
Although not stated in the KB, the issue can be resolved by turning off and turning On the Maintenance mode for the vCenter connection as such: