Spoiler: FYI

You can sell your Melodyne 5 Essential license, but only if it was purchased as an independent retail product. If the serial number was obtained as a free promotional coupon, came as part of a hardware bundle, or was upgraded to a higher tier, it cannot be sold

Licenses obtained for free as "coupons" or upgrades (like those included with hardware or bundled with third-party software) cannot be resold. You also cannot resell licenses bought via credit card within the first 3 months.
If your license is eligible, the transfer must be handled officially by Celemony support.
The step-by-step process:

1. Check Eligibility: Log in to your Celemony User Account to verify your serial number does not state "coupon" or "upgraded".
2. Contact Support: Submit a support ticket to Celemony with the new owner’s name and email address.
3. Deactivate: Uninstall the software from your computer and remove any associated iLok activations.
4. Transfer: Celemony will remove the license from your account and register it to the buyer's new account.

 

Does it fall under the category of "You can sell your Melodyne 5 Essential license, but only if it was purchased as an independent retail product." ?

If the developer doesn't allow for it, then it is illegal and therefore considered warez -which is obviously, not allowed here at the forum.

It is always best to check with the developer before buying/selling so there are no hidden surprises with transactions and registering licenses, such as this.