If the error persists after checking your connection, try these steps:
Which would you prefer?
Incorrect system time can cause security handshake failures. If possible, use the in Recovery Mode to set the correct date manually. Apple Support Community Advanced Solutions activate mac failed to create activation request
If you’re stuck on the activation screen: If the error persists after checking your connection,
: If your Mac's date and time are incorrect, the secure connection to Apple will fail. You can often fix this in Recovery Mode by opening Terminal (under the Utilities menu) and typing date to check the current time, or ntpdate -u time.apple.com to sync it. Advanced Solutions activate mac failed to create activation request
Activation certificates are ephemeral. A wrong system clock breaks the cryptographic validity check.