Hello Jayneel Dave
Welcome to Microsoft Q&A Platform, thanks for posting your query here.
The error message you provided indicates that the D-Bus System Message Bus failed to start, which could be preventing the virtual machine agent from starting up properly.
To troubleshoot this issue, trying the following steps and see if that helps:
-Restart the virtual machine, sometimes this will resolve the issue.
-As you are unable to connect to the virtual machine using SSH or remote desktop, you can try connecting to the Azure VM using Console and run below command:
systemctl status dbus.service
This will display the status of the D-Bus System Message Bus service and provide more information about why it failed to start.
Other thing you can try is to reinstall the agent, reinstalling the VM agent can help to resolve issues with the agent that may be preventing it from running properly.
Please refer to these docs on how to install Azure VM agent on Linux:
https://learn.microsoft.com/en-us/azure/virtual-machines/extensions/agent-linux#installation
https://learn.microsoft.com/en-us/azure/virtual-machines/troubleshooting/install-vm-agent-offline
https://learn.microsoft.com/en-us/azure/virtual-machines/extensions/update-linux-agent
Hope this helps.