Hi,
Floating subscription must be used in this case and your VM must have access to your license server.
There was a series of articles at https://support.smartbear.com/articles/testcomplete/ ("Cloud Testing With TestComplete", "Preparing Your Cloud Environment for Automated Testing", "Cloud Test Automation Tutorial", etc.) dedicated to AWS. Considering that TestLeft utilizes TestComplete/TestExecute runtime engine, I think that you may go through these articles and check if they are of any help for TestLeft on Azure.
