The MX (Mail Exchange), is a DNS record responsible to redirect the domain to a mail server, the MX record indicates how the email messages must be delivered following the SMTP (Simple Mail Transfer Protocol) protocol, just like the CNAME records, the MX must point to another domain.


An example of a MX record:


Name/HostTypePriorityValue
@MX10mailhost1.example.com
@MX20mailhost2.example.com


The "Priority" number means that the lower number has priority to send and receive the emails, if the mailhost1 fails, the server will use mailhost2 as default.


The priority number is optional, it depends on the mail server.


For example, Google Workspace has 4 priority numbers:


Name/Host
Time to Live (TTL)Type
Priority
Value
@3600MX1ASPMX.L.GOOGLE.COM
@3600
MX
5
ALT1.ASPMX.L.GOOGLE.COM
@3600
MX
5ALT2.ASPMX.L.GOOGLE.COM
@3600
MX
10ALT3.ASPMX.L.GOOGLE.COM
@3600
MX
10ALT4.ASPMX.L.GOOGLE.COM






And Ionos has only two:


Name/Host
Time to Live (TTL)
Type
Priority
Value
@3600MX10mx00.ionos.com
@3600MX20mx01.ionos.com


If you already has a mail server before pointing the domain to our Cloudflare, you must send the MX records of your mail host for our support team add it on the DNS zone.


If you don't send the MX records for our support team, your emails will no longer work after you point the domain to us, causing trouble for you and your clients.


If you would like to know more about the domain change and DNS settings, check our article about the domain change process: Domain Change: How can I proceed to change my domain