I am having some issues with SMTP setup in Auth0 where external users are not receiving our emails. I have set up SPF (basic) and DKIM activated, I have whitelisted all IPs stated in the Email Provider page, when I analyze the email header sent on mxtoolbox (result at: https://mxtoolbox.com/Public/Tools/EmailHeaders.aspx?huid=7a6a813e-a221-462b-b491-29df758b5f50) I get failed on “SPF Failed for IP - 18.104.22.168” (this IP changes, and are amongst the listed ones from the Email Provider page, which I already whitelisted in Office365 admin pages).
Also, it seems like, although the DKIM is active, the signature is not added when emails are sent using Auth0.
I’m not really sure what the underlying issue is, since it complains about SPF issue I’ll start with mentioning my SPF record, which has the value: “v=spf1 include:spf.protection.outlook.com -all”
Hope you can help
Edit: Just to clarify, I have SMTP set up with same credentials in my C# project, from here the emails seems to be delivered as expected to recipients.