MTA-STS checker

Problems this finds

Your mailbox settings point to an address that doesn't exist

Senders trying to reach you can't connect to that address. Emails to you may be delayed, or, if there's no working backup, not arrive at all.

Your mailbox settings point to an address outsiders can't reach

One of your mailbox settings points to an internal network address, so senders outside your office can't deliver there. Whoever manages your mail server will need to supply the correct public address.

Some emails sent to you may not arrive

Your mailbox settings point to a shortcut name instead of the real address. Many senders follow it, but some refuse, so a few customers' emails may never reach you and you won't know.

This domain is set to not receive email

Your settings clearly tell senders this domain doesn't accept email, so they get an immediate, clean bounce. That's correct if you don't use it for email; if you do, it needs changing.

Optional: add encrypted delivery protection for emails sent to you

Emails to you are usually encrypted on the way, but this makes it required, so an attacker can't quietly switch encryption off and read them. Setting it up needs help from whoever runs your website.

Some emails to you could be refused because of a settings mismatch

Your encrypted delivery protection doesn't list every server that receives your email. When it's fully on, senders refuse to deliver to the missing one. Whoever set it up needs to add it.

Your encrypted delivery protection is still in test mode

Problems are reported but nothing is blocked yet, so the protection isn't active. Once the reports show no problems, whoever set it up can switch it fully on.

Your encrypted delivery protection is switched on but not working

Your settings announce this protection, but the file it depends on can't be reached, so senders ignore it. Your email still arrives. Whoever runs your website will need to fix the file.

Your business can't receive email at this domain

There are no mailbox settings, so emails sent to you, like customer inquiries and replies to your quotes, bounce back. If you don't use this domain for email, you can say so instead.

Your business receives email through one server with no backup

If that server has an outage, emails to you are delayed, and lost if it lasts for days. Many providers use just one on purpose, so check your provider's instructions before changing anything.