If you manage your own DNS records and your DNS host does not support all the DNS records that Office 365 needs, some Office 365 features won’t work. We recommend that you transfer your domain to a registrar that supports all required DNS records.
Providers that support all required DNS records:
Dynadot
eNomCentral
Europe Registry
GoDaddy
Hover
MyHosting.com
Name.com
Nearly Free Speech
Nettica
Network Information Center (NIC)
Network Solutions
Register.com
If SRV records are not supported, the following Office 365 features are not available:
Skype for Business Online IM and presence integration with Outlook Web App
External communication (federation) with Skype for Business Online users in other organizations.
Public Internet Connectivity (PIC) with Skype for Business Online users signed in with a Microsoft account (formerly known as a Windows Live ID).
If multiple CNAME records are not supported, you have to choose between the following features for Skype for Business Online:
Email desktop clients and mobile clients can use Autodiscover to automatically find the Exchange Online service so that users can sign in without having to enter a server name.
Skype for Business Online desktop clients can use Autodiscover to automatically find the Skype for Business Online service so that users can sign in without having to enter a server name.
Skype for Business Online mobile clients can use Autodiscover to automatically find the Skype for Business Online service so that users can sign in without having to enter a server name.
If SPF/TXT records are not supported, other people may be able to use your domain to send spam or other malicious email. SPF records work by identifying the servers that are authorized to send email from your domain.