Email deliverability guides
A successful send does not tell you where a message landed. To investigate spam placement, first separate messages the receiving server accepted from messages it delayed or rejected.
EXPERTISE IN ACTION
Your platform may report a message as delivered after a receiving server accepts it. The recipient’s system can still filter that message into spam. Confirm the result with an affected recipient or available placement evidence instead of treating the delivery status as proof of inbox placement.
A temporary SMTP response can cause your platform to retry, while a permanent rejection indicates that attempt failed. Save the complete response, destination, time, and sending source. Treat a queue problem separately from an accepted message in a spam folder.
Look for supporting evidence before changing domains, content, or sending platforms. Differences in audience behavior and measurement can affect opens. Identify which messages and recipients are affected, and compare them with a period when delivery appeared normal.
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Compare mailbox providers, sending domains, platforms, and message types. Are password resets affected as well as campaigns? Does the problem appear at one provider or across several? This tells your team where to gather more evidence.
Inspect the recipient-side authentication results for representative messages. A DNS record alone does not prove that every platform uses the correct identity. Our SPF, DKIM, and DMARC guide explains what to compare.
For Gmail traffic, review the available Postmaster Tools signals and the Gmail sender guidelines. Complaints, unexpected volume changes, and the quality of the audience deserve attention alongside technical configuration.
Record infrastructure migrations, new sending sources, audience imports, and template changes. Compare affected traffic with an unaffected flow where possible. A change near the start of the incident is a hypothesis to test, not proof of the cause.
Choose a specific hypothesis, an accountable owner, and a way to observe the outcome. Avoid replacing several parts of the environment at once: it makes the evidence harder to interpret. Document what changed and how provider responses and recipient outcomes behaved afterward.
EXPERTISE IN ACTION
No. Authentication establishes part of the sender’s identity; receiving networks also apply filtering decisions. A passing result is useful evidence, but it does not promise inbox placement.
First determine what the current evidence supports. A rushed migration can introduce another set of authentication and operational changes before the original issue is understood.
Bring in support when important messages remain affected, several teams own different pieces of the infrastructure, or the available evidence is difficult to reconcile. InboxGenius provides email deliverability consulting through an ongoing monthly retainer. We do not guarantee placement or sell hourly consulting.
LET’S MAKE EMAIL DELIVER.
Tell us your sending platforms, affected providers, approximate volume, and when the problem began. Keep passwords, API keys, and recipient lists out of the inquiry form.
