Hybrid AD joined machines not showing up in Azure AD

We were trying to connect on-premises AD based machines to Azure AD using GPO settings. Everything should work fine, is what we thought. However, the machines didn’t show up in Azure AD.

Troubleshooting started. Does the user account have license assigned, is the GPO applied properly etc etc. After 2 days of trail and error, we found that these machines were not in the OU which was being synced through Azure AD connect tool. Adding the machines in the OU immediately resolved the issue.

Hope this helps those who are facing this issue.