Free tool
SPF record checker.
SPF tells receivers which servers may send mail for your domain. A missing, duplicated, or too-permissive record sends cold email straight to spam. Enter a domain to look it up and grade it.
Stop babysitting deliverability
CogniLead provisions SPF/DKIM/DMARC, warms the pool, and pauses a domain before its reputation drops. You bring the leads.
Also try the DMARC checker.