If you are encounter an error related to add-on/parked domains not being allowed while trying to create one, you have to enable add-on/parked domains for that particular account from your reseller WHM. (This is applicable only if you are the reseller of that account. If you own only the account, you’ll have to either contact your reseller or the support.)
Follow these steps to enable add-on or parked domain –
1. Log in to WHM.
2. Click on Modify Account from the options.
3. Select the domain for which you are trying to enable add-on/parked domain.
4. The filed that specifies the number of addon/parked domains that the account can have, will be zero. Increase it to a number of your choice/requirement.
5. Try adding add-on/parked domains from the cPanel of that particular account.