Why are you unable to send the transfer authorization email to any address I want?
The registrant contact and administrative contact listed in the Whois are the only parties that can authorize a domain transfer as stated by ICANN. Therefore, the authorization email can only be sent to the address listed in those two fields.
If you would like the authorization email sent to a different address, you would need to update your contact records with your current registrar first.
Find out more about the domain transfer process.