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Mailbox troubleshooting · Practical guide

SMTP works but IMAP fails: isolate incoming mailbox access

A successful SMTP test proves only the tested sending path. IMAP has its own endpoint, transport and access requirements, so troubleshoot it separately.

Reviewed · Examples are illustrative

Who this helps: Mailbox owners and service operators diagnosing outreach connections.

Define the decision

The operational risk is missed conversation context. If sending continues while incoming synchronization is broken, a pending follow-up may be inappropriate even though the mailbox appears partly healthy. Review both the technical failure and responses received during the outage before resuming normal campaign work.

Work through the procedure

  1. Record the exact SMTP success and IMAP error with timestamps. Avoid summarizing both as a generic connection failure.
  2. Check the incoming host, port and encryption mode against the mailbox provider's current instructions.
  3. Confirm the authorized identity has incoming protocol access. Webmail access alone does not prove IMAP authorization.
  4. Inspect a controlled reply in the provider inbox, then verify whether Zintara can see it after repair. Review real replies that arrived during the gap.

Worked example

The following is a synthetic example for this procedure, not a customer result or performance benchmark.

SMTP test: passes
IMAP test: authentication rejected
Provider webmail: controlled reply visible
Conclusion: focus on incoming authorization and configuration
After repair: verify sync and review missed replies before continuing follow-ups

Read the result

The provider inbox confirms that the reply exists upstream. It does not identify the IMAP error's cause, but it narrows the investigation away from whether the recipient sent the message. Preserve the error and connection settings without exposing passwords in a ticket or screenshot.

Check before moving on

  1. Use the same intended mailbox identity for both paths.
  2. Check folders or rules when the message is absent from the provider inbox.
  3. Verify the selected campaign sender after updating the connection.

Limits and next action

Zintara's current sync path reads INBOX; it is not a promise to import every folder or historical archive. Its custom connection testing requires secure incoming access. Do not disable protections as a generic troubleshooting step or infer full sync health from a sending success.

Source: Zintara unified inbox product context

Source references

Worked examples are illustrative. Editorial procedures are suggested methods, not measured performance claims or promises of additional product features. Check current provider guidance before changing mailbox configuration.

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