What is the issue?

Some customers add include:spf.titan.email to their SPF records, which is not the TitanHQ SPF include: statement. include:spf.titan.email belongs to a different company, called Titan.

What is the solution?

If you are using https://cloud-out-c.spamtitan.com for outbound mail, the TitanHQ include: statement is:

include:_spf_cd.spamtitan.com

If you are using SpamTitan Private Cloud, outbound and inbound mail go through the same server(s), so you can add mx to your SPF record.