Intermedia 550 5.7.1: spam filter rejection

What it means

Intermedia hosts Microsoft Exchange for small and mid-sized businesses. Its bounces mostly use standard Exchange wording, so a 5.7.1 from an Intermedia tenant usually reads like a generic Exchange spam or content filtering refusal. What tells you it is Intermedia is the host names in the bounce, which typically sit under intermedia.net or serverdata.net.

The enhanced code 5.7.1 (RFC 3463) means delivery was not authorized. At Intermedia that most often comes from the spam filtering layer in front of the tenant’s mailboxes, which scores inbound mail and can be tuned per customer. The decision is per organization, so another Intermedia customer may accept the same message.

Because it is a hosted platform, the recipient’s admin does not manage the servers. They change filtering through Intermedia’s HostPilot control panel or by asking Intermedia support.

Likely causes

• Your message scored as spam under the tenant’s filter settings.
• Your sending IP has a poor reputation or appears on DNSBLs the filter uses.
• The tenant added your address or domain to its blocked senders.
• Failing SPF or DKIM on a domain with a strict DMARC policy.

Checks that apply

• MX Lookup Shows whether the recipient domain’s MX records point at Intermedia, confirming who hosts the mailbox.
• Blacklist Check Checks your sending IP on 40 blocklists, a common input to hosted Exchange spam filters.
• SPF Check Tests your SPF record, since a fail combined with DMARC enforcement can trigger this rejection.

FAQ

Is this a Microsoft 365 bounce?

No. Intermedia runs its own hosted Exchange platform. The wording looks like Exchange, but Intermedia’s filters and support handle it, not Microsoft’s.

Can the recipient whitelist me?

Usually yes. A tenant admin can allow your domain in the spam filter settings, which is often faster than waiting for reputation to recover.