@KUSHGARG-1386 Are you using a free azure subscription? It looks like you have reached a quota limit for the instances you want to spin up in this cluster. You can go ahead and delete any unused clusters and retry this step again or navigate to the Usages + quotas page from the left pane of Azure portal and configure the quotas if permitted. More details about Azure ML workspace related quotas are documented here.
If the above mentioned limits cannot be changed then you might need to upgrade your subscription to pay as you go and try to increase the quotas from the Usages + quotas page