Email Deliverability Guide.

Check your domain's authentication records first, then measure where a real email lands. The guide above reads your SPF, DKIM, DMARC and MX records live, checks domain blocklists and domain age, and turns the results into a ranked plan. Paste the headers of an email you sent to confirm it passed authentication. To see inbox or spam per provider, run an inbox placement test.

Fix authentication first, then protect your reputation. Publish one valid SPF record, turn on DKIM with your provider and add a DMARC record. Then raise volume slowly from new mailboxes, send only to verified addresses, keep spam complaints under 0.1% and make unsubscribing easy. Content comes last: plain, specific emails with few, visible links. The plan above puts these in order for your domain.

Usually because the receiving provider cannot confirm the email is really from you, or your domain's reputation is weak. Common causes are a missing or broken SPF, DKIM or DMARC record, a new mailbox sending too much too soon, a list with invalid addresses, and recipients marking your mail as spam. Run the guide above to see which of these apply to your domain.

Every sender needs SPF or DKIM, valid forward and reverse DNS for its sending servers and a spam rate below 0.3%, and Gmail also requires TLS. Senders of about 5,000 or more messages a day to their personal users also need both SPF and DKIM, a DMARC record (p=none is enough), a From domain aligned with SPF or DKIM, and one-click unsubscribe on marketing mail. Outlook.com applies its rules from 5,000 messages a day.

Mostly not, because Gmail and Outlook.com count only mail sent to their personal accounts. Gmail says its sender guidelines do not apply to messages sent to Google Workspace accounts, and Microsoft's rules cover Outlook.com, Hotmail and Live addresses, not Microsoft 365. Business mail systems still check SPF, DKIM and DMARC, so set them up anyway. Once you reach Gmail's bulk threshold, that status is permanent.

No. Gmail, Yahoo and Outlook.com accept p=none as meeting their requirement. A DMARC record must exist, carry a policy tag and, for bulk senders, pass through an aligned SPF or DKIM result. Stricter policies, quarantine or reject, protect your domain from spoofing. Move to them after your aggregate reports show all of your own mail passing, or you risk blocking your own email.

Far fewer than the provider limits, which are ceilings that stop a mailbox rather than safe volumes. Google Workspace allows 2,000 messages a day per user (500 on a trial account) and Microsoft 365 allows 10,000 recipients a day. For cold email, start a new mailbox low, raise it gradually, and add mailboxes to grow rather than pushing one mailbox towards its ceiling.

There is no fixed number of days; it depends on how recipients respond. Gmail's guidance is to start with a low volume to engaged recipients and increase it slowly. Raise volume while replies stay healthy and bounces stay low, and hold it, rather than pushing on, when spam placements or bounces appear. SendCanyon's warmup raises volume only while engagement is confirmed.

We keep the domain you checked, your answers and the results for 90 days, with your IP address and browser, to prevent abuse. If you paste headers or a full message, we read it to run the checks and keep only the results, never the message. A problem you describe in your own words is used once to fill in the questions and is not saved.