If you use a free Apple ID with Cydia Impactor, the Phoenix app certificate will expire after 1 week and needs to be renewed before you can use Phoenix jailbreak again. To renew it, you must reinstall the jailbreak using Cydia Impactor, so, going back to the tutorial above, repeat from Step 3 to reactivate. If your Apple ID is of a paid developer account, the certificate expires after one year.