The admin consent button should be working properly. Are you sure you have the right permissions to grant admin consent?
Which browser are you using? Can you try again now and see if it's working as intended? It may have been a transient issue with your network.
Have you checked that the permissions for your respective AAD Application Registration have been granted to the service principal/enterprise application?
You can check this by going to the enterprise application's permissions and seeing if the permissions are there or not.
Can you explain why you think it's not working properly?