A customer would like to use a service called Zywave to send out newsletters to his clients. He is also using MS Office 365. Integratio of the Zywave application with his Outlook 365 email requires that several changes be made to his DNS records. The CNAME that The Zywave folks specify is OK, but the TXT record returns the error shown in the attachment. Apparently, Outlook online believes that the hostname should not have an underscaroe as its first character. The Zywave help desk insists that their specification is correct.
What am I missing here? Is Outlook enforcing something that is not commonly enforced? Or, did Zywave send us an incorrect hostname?