Each account has an option to enable additional security feature for domain push.

NOTE: Do not mix up Push authorization code with Transfer authorization code (EPP). The latter is needed only for domains transfer between registrar, while the Push auth code is needed when transferring domains between Namecheap accounts

If you would like your account to accept any domain pushed to your account, please select “Allow All” under Push Security Settings in Manage Profile section.

If “Requires Authorization” option is selected, a code will be required for domain push to your account. “One time use code” is valid one time only and gets reset after being used. You can also set a permanent code for domain pushes to your account.