SPF Authentication: SPF-all vs ~all (What is the difference between Spf record -all vs ~all?)
SPF stands for Sender Policy Framework.
means “SPF Failed and the email should be rejected.”
SPF lets the domain administrators to specify what mapped sub-domain or IP addresses are allowed to send emails on a domain's behalf. The setting is usually entered as a TXT record under domain DNS settings. If you want to read up more, then check out the details here.
You can read about DMARC settings for Google Apps.
If settings are for Microsoft 365 / Office 365:
Type = TXTName = _dmarc
Data = v=DMARC1;p=quarantine;rua=mailto:email@example.com; pct=10; adkim=r; aspf=r;
Type = TXT
Name = @
Data = v=spf1 include:spf.protection.outlook.com -all