Error activating product key: (23): The product key has already been activated with the maximum number of computers.

Problem: The license is already in use and you are unable to activate your license. 

Root Cause: This error means that you’ve exceeded the activations on the product key.

Solutions:

1. Verify that your license has enough activations available for your needs; reach out to your Customer Success representative if not.
2. Verify that you’ve deactivated the license on servers you are no longer using; to free up the activation for your new server, you can run the appropriate deactivate command on the server you wish to deactivate, e.g. for online '$ sudo <product> license-manager deactivate'. If you no longer have access to the old server(s), you can use this application to deactivate all activations on a given key. Note that this will deactivate ALL activations on the license key. If your key has more than one activation and you do not want to deactivate all of them at once, please contact Support so we can deactivate just the activation you need while leaving the others intact.
3. If you are renewing, make sure you've run the deactivate command before you run the activate command on your server.

Outcome: After you have successfully deactivated the license usage, and successfully activated the product key, you can check the status of the license by running this command $ sudo <product> license-manager status on the server: 

Further reading:

I'm having a problem with my license; how do I fix it?