Question 1

Why is my email going to spam?

Accepted Answer

The most common causes, in order: (1) authentication misalignment between DKIM and From domain; (2) damaged domain reputation from prior bad sends; (3) content patterns like excessive caps or suspicious URLs; (4) low engagement from inactive subscribers; (5) shared IP neighbors (rare on Inbox OSS). The dashboard Deliverability tab shows which of these is hitting you.

Question 2

How do I set up DKIM, SPF, and DMARC?

Accepted Answer

DKIM: publish the CNAME shown in the Domains tab (e.g. s1._domainkey.yourdomain.com → s1._domainkey.<slug>.mail.inbox.onesourcesoft.com). SPF: add include:inbox.onesourcesoft.com to your existing SPF record. DMARC: start with v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com and move to p=quarantine then p=reject after 30 days of clean reports.

Question 3

What is the difference between hard and soft bounces?

Accepted Answer

Hard bounce: permanent failure (address does not exist, domain does not exist, mailbox closed). Auto-suppressed immediately. Soft bounce: transient failure (mailbox full, greylisting, temporary block). Retried with exponential backoff; three consecutive soft bounces from the same address promote it to a hard bounce.

Question 4

What rate limits apply to the API?

Accepted Answer

Free tier is 600 requests/second per API key. Paid tiers are 6000 req/sec. The headers X-RateLimit-Remaining and X-RateLimit-Reset show your current state. Burst-tolerant: short spikes up to 2x your limit are allowed.

Question 5

How do I troubleshoot a failed send?

Accepted Answer

Order of debugging: (1) Check the dashboard event log — every failure has a reason. (2) Verify the sending domain is fully authenticated (DKIM, SPF, tracking CNAMEs all green). (3) Check Suppressions — suppressed addresses return success at API time but produce no send. (4) Check rate-limit headers. (5) Email support@inbox.onesourcesoft.com with the message ID for same-business-day response.

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