Fix · nginx
Fix “Email sender authorization (SPF)” on nginx
Publish an SPF TXT record listing only your real senders and ending in -all.
No server-level snippet for this control on nginx; apply the guidance below.
Verify the fix
Re-run the Email sender authorization (SPF) check after deploying. Test config changes in staging first and keep a rollback: a wrong header can break a site faster than a missing one.
Other stacks: Apache · Caddy · Express / Node · Cloudflare