Set up SPF to identify valid email sources for your Microsoft 365 ...
Learn how to update a Domain Name Service (DNS) record to use Sender Policy Framework (SPF) with your custom domain in Office 365.

Troubleshoot email authentication in Microsoft 365
Troubleshoot SPF, DKIM, and DMARC email authentication failures in Exchange Online and Microsoft 365 with quick-reference tables and detailed guidance.

how do I fix email with DMARC, SPF and DKIM issues?
Emails that I send are ending up in junk or spam or are being quarantined. The problem is related to the DMARC, SPF and DKIM settings.

Email authentication - Microsoft Defender for Office 365
Admins can learn how email authentication (SPF, DKIM, DMARC) works and how Microsoft 365 uses traditional email authentication and composite email authentication to allow and block spoofed messages.

How can make a change to the SPF record for my DNS which is hosted by ...
Yes, it is possible to edit the SPF record for your domain in Office 365, including adding additional IP addresses or mechanisms such as the "p4" mechanism you mentioned. However, modifying DNS records, including SPF records, typically requires administrative access to your domain's DNS settings.

SPF/DKIM Failures from External Sender to MS Outlook Hosted Domains
We are a legitimate sender running our own mail server (not hosted on Microsoft 365), with proper SPF and DKIM configuration. In our DMARC reports, we’re seeing that some messages to recipients using Microsoft Outlook intermittently fail SPF or DKIM…

External Domain Name System records for Microsoft 365
SPF records are TXT records that help to prevent other people from using your domain to send spam or other malicious email. Sender policy framework (SPF) records work by identifying the servers that are authorized to send email from your domain. You can only have one SPF record (that is, a TXT record that defines SPF) for your domain.

Connect your domain by adding DNS records - Microsoft 365 admin
SPF TXT record - This record is optional but highly recommended. The SPF TXT record helps prevent email spam. For more information on SPF TXT records, see Help prevent email spam (Outlook, Exchange Online) by adding appropriate DNS records in this article. If an SPF record already exists for the domain, don't create a new one for Microsoft 365.

Email domains and sender authentication - An Azure Communication ...
SPF (Sender Policy Framework) SPF RFC 7208 is a mechanism that allows domain owners to publish and maintain, via a standard DNS TXT record, a list of systems authorized to send email on their behalf. Azure Communication Services allows you to configure the required SPF record that needs to be added to your DNS to verify your custom domains.

Fix NDR error 5.7.23 in Exchange Online - Exchange
Verify the SPF DNS record for your domain. To do this, we recommend that you use a publicly available SPF or DNS record checker on the web. Provision all of the domains you own. We limit the number of emails with unprovisioned domains that a tenant can send. Add your on-premises IPs, if any, to the SPF record of any domains you send for.