It is important when adding SPF to your domain, that you correctly identify all possible sources of email that may be sent from your domain so that these can all be included. Failure to include an authorised mail server could result in some/all of your email not being delivered. Below are some possible sources that your email may originate from, however, this list is by no means exhaustive and may differ in every case.
- Email server (Tibus, Microsoft O365, Gmail…)
- Email smart hosts/relay servers
- Web server that hosts your website
- Bulk Email service (Mailchimp, Mailgun, Sendgrid…)
- Other cloud-based services (CRM, Room booking…)