SPF Record type 99 was deprecated in April 2014 per RFC7208. It is now best practice to configure framework policies in a TXT record, which shares the same format type as an SPF record. RFC studies have found that using SPF records can lead to interoperability issues.
In accordance with RFCs, Constellix no longer allows the use of SPF records for newly added domains or in new configurations for existing domains.
Note: Constellix will continue to support modifications and deletions of SPF records that currently exist in your account.
For existing configurations that use SPF records, we recommend that you also store identical SPF information in a TXT record.
Here is our documentation for creating TXT Records.