Problem

Several users have commented and posted on different networks about the error that appears when adding virtual machines to their host pool, the error is when the VMs want to join to the AD.

The first thing we need to know is that if we add or create a new hostpool (as in my case), the deployment will tell us Azure that everything is correct, that is, as if the machines have joined the AD. Here I show the deployment with everything correct.

Now if we check the status of our hostpool machines, we will see that it tells us the total number of VMs and the option of which one we can connect to and which one we cannot. In my case we see that we can supposedly connect to one and not to the other.

When testing the connection, it fails on both machines. This is normal since if we check the health status of both we see the following.

Basically it tells us that there is a problem joining the domain with the VM.

Solution

Below I show the solution that has worked for me, from different tenants, different subscriptions that had the same problem.

1. We are going to go to our subscription and in it, in the setting section, we are going to click on Resource provider as shown in the following image.
   
   
2. Next we look for the provider "Microsoft.DesktopVirtualization"
   
   
3. We select it and then click on "unregister"
   
   

    

4. Now what we are going to do is re-register, that is, we click on "register"
   
   

    

5. Confirm that register is correct again.
   
   

    

6. Now we deploy AVD again and add the VMs we need to our Hostpool, and in this case I have chosen Enter ID to do the Join *you can select your preferens)
   
   

    

7. Validate de new deployment
   
   

   As we see here, the deployment has also indicated that it was correct, so we are going to confirm it.

   

   Here we can see that we already have the machines ready for the session.

   

    

    

   

    

   

    

   

    

   I hope this helps you solve the problems you are having with VMs and hostpools.