If you are trying to activate a retail key on an Evaluation edition, the activation will fail because retail keys cannot be applied directly to an expired or active Evaluation edition. Convert the Evaluation edition to the full Standard or Datacenter edition first before attempting to activate.
If you are trying to activate a retail key on an Evaluation edition, the activation will fail because retail keys cannot be applied directly to an expired or active Evaluation edition. Convert the Evaluation edition to the full Standard or Datacenter edition first before attempting to activate.