0xC004C020 and 0xC004F074: the ESU key is out of activations, or no KMS answered
0xC004C020 means the MAK is out of activations; 0xC004F074 that no KMS host answered. Activate ESU with its own Activation ID, and check the base licence.
Office 0xC004C020: your MAK key has run out of available activations
Error 0xC004C020 means the Multiple Activation Key has used every seat it was sold with. See how to check the count and what to buy next.
0xC004C020 and 0xC004C021: Your MAK Has Run Out of Activations
0xC004C020 and 0xC004C021 mean your Multiple Activation Key has used every seat it was sold. See how to check remaining count and how to add more seats.