Like I mentioned, you should remember to put into your SPF record the apps that send emails on your behalf, but are using their own SMTP.
Setting SPF and DKIM will help you protect the good reputation of your domain, and thus improve the deliverability of your emails.1 Sep 2016
What is DKIM and SPF?
In a nutshell, SPF allows email senders to define which IP addresses are allowed to send mail for a particular domain, while DKIM provides an encryption key and digital signature that verifies that an email message was not forged or altered.11 May 2018
Does Dkim improve deliverability?
Inbox deliverability is never a guarantee, but understanding how DKIM affects email deliverability can improve your chances of landing in the inbox rather than the spam folder. DKIM serves as a digital signature in the form of a snippet of code on your emails and from your domain record.7 Sep 2017
Does dmarc require DKIM and SPF?
DMARC not only requires that SPF or DKIM PASS, but it also requires the domains used by either one of those two protocols to ALIGN with the domain found in the “From” address. Only then will DMARC PASS.
What is a SPF record for DNS?
A Sender Policy Framework (SPF) record is a type of Domain Name Service (DNS) TXT record that identifies which mail servers are permitted to send email on behalf of your domain. The purpose of an SPF record is to detect and prevent spammers from sending messages with forged From addresses on your domain.