Email Spam clean up

We are suffering from our emails going into spam folders. We realise there's lots of things we can do to "authorise" our domain and email address, but need assistance doing this.

A search of ChatGPT gave me the pointers below, but I would want to investigate all options.

At the moment, it looks like creed.london is missing SPF, DKIM, and DMARC. This absence is causing your emails to be treated as unauthenticated and, in many cases, marked as spam. The fix is to set up:

SPF to declare authorized sending servers

DKIM to sign outgoing messages cryptographically

DMARC to define how failures are handled, and enable reporting