Your Azure Virtual Machine hung while rebooting or stopping/deallocating.  You cannot start or stop the Azure Virtual Machine from the normal portal GUI overview as it is greyed out.  Try one of the following methods to force a reboot on your Azure Virtual Machine.

Force Reboot Azure VM from GUI:

  1. In the Azure Portal go to the affected virtual machine and select Serial Console from the Support + troubleshooting section.
  2. Select Reset VM or Reset VM(Hard)

Force Reboot Azure VM from CLI:

Open the Azure Portal and click on the top right to open the Azure Cloud Shell.

From the Powershell prompt in the Cloud Shell type AZ and press enter to open Azure CLI.

From the CLI prompt enter the command:

(Update with your ResourceGroup and Virtual Machine name.)