Check the whole path
Follow the sequence below from start to finish. The order matters: later steps assume the earlier ones are done.
- Submit a valid test entry on the published domain.
- Confirm the browser shows the expected success or error state.
- Inspect the network response for a rejected request.
- Check the configured recipient, sender verification and spam folders.
- Review provider logs before changing the form UI.
- Retest with a unique subject or reference so the message is easy to trace.
Common causes
Here are the key things to get right. None of them are complicated on their own, but skipping one tends to undermine the rest.
- Required field or validation mismatch.
- Form endpoint or integration not connected on the published site.
- Unverified sending domain or recipient configuration.
- A provider suppression, bounce or spam placement.
- A success state shown before the downstream email job completes.
Never tell a visitor an email was delivered unless the system has actually confirmed the relevant step.
Diagnostic checklist to run in order
The list below breaks this down into the parts that matter most. Read through each one and note anything that applies to your own setup.
- Does the form work in preview but fail on the published domain?
- Does the network request return a success status but no email arrives?
- Is the recipient address correct and not filtered by their own mail rules?
- Has the sending domain's verification lapsed or changed?
- Are duplicate submissions being silently deduplicated by the provider?
Handover notes after a fix
Before making changes, work through the points below. Each one covers a different part of the picture, so treat them as a set rather than picking favourites.
- Document the root cause and the exact setting changed.
- Add a recurring monthly test submission to catch silent regressions.
- Note the provider dashboard location for future log checks.