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Hello PythonAnywhere team,

I'm getting several DNS email authentication errors on my custom domain (prometheanconduit.ai) which is CNAME'd to your nameservers. MxToolbox domain health check is reporting these issues:

Critical Errors (3): - DMARC (dmarc@pythonanywhere.com): Quarantine/Reject policy not enabled - MX (pythonanywhere.com): Missing quarantine/reject policy (requires 100% enforcement) - SPF (pythonanywhere.com): Missing quarantine/reject policy (requires 100% enforcement)

Warnings (3): - SPF has duplicate includes - SMTP reverse DNS doesn't match SMTP banner - SOA Serial number format is invalid

Google and Yahoo require DMARC for email acceptance, so this is affecting email deliverability. Can PythonAnywhere enable these email authentication policies on the pythonanywhere.com nameserver infrastructure?

Thanks!

Hi there,

The key point here is that PythonAnywhere does not provide email hosting or outbound email services for custom domains, and we don’t manage email-related DNS records (MX, SPF, DKIM, DMARC) for customer domains.

A few clarifications that should help: • Your domain prometheanconduit.ai is CNAME’d to PythonAnywhere only for web hosting. This affects HTTP/HTTPS traffic, not email. • The DMARC, SPF, and MX warnings you’re seeing from MxToolbox are referring to email configuration, and in some cases they are inspecting pythonanywhere.com, not your own domain. We can’t change DMARC/SPF policies for pythonanywhere.com to satisfy third-party email tools, and those policies are not intended to be used for customer email anyway. • If you want email deliverability for @prometheanconduit.ai, you need to: • Use an external email provider (Google Workspace, Microsoft 365, Fastmail, etc.) • Configure MX, SPF, DKIM, and DMARC records for prometheanconduit.ai at your DNS provider (registrar or DNS host)

PythonAnywhere is only responsible for serving your website content. Email authentication policies must be set on your domain’s DNS, not on ours.

So to answer your direct question: No, we can’t enable or modify DMARC/SPF/MX policies on the pythonanywhere.com infrastructure for customer email deliverability, and it wouldn’t be appropriate even if we could.

I assume that you or the site that sold you your domain name are using MxToolbox to ping your services and by default is pinging for an mail server that hasn't been defined.

If you want a mail server I recommend to find an email provider and sanity-check whether your domain setup (web vs email) is separated correctly.

If you do not plan to have a mail server, then you should turn off that MxToolBox ping.