WorkMail Client Setup in Mac iOS not working. Asking for Internal URL and External URL. Not sure what to give

WorkMail Client Setup in Mac iOS not working. Asking for Internal URL and External URL. Not sure what to give. Try to setup the WorkMail using Microsoft Exchange option.

Followed all steps on this link

https://docs.aws.amazon.com/workmail/latest/userguide/connect_mac_mail.html

Instead of accepting after password screen it takes to a new screen asking for Internal and External URL. And I am not able to find a URL that can be given there and not able to setup the client.