Troubleshoot inbound emails that do not appear in your Crisp Inbox and understand why some messages may be rejected before they reach your team.

Inbound email delivery depends on your Crisp email settings, custom domain DNS records, sender authentication, and Crisp anti-spam protection. Start with the checks below, then use any bounce or SMTP error returned to the sender to identify the exact cause.

In this article:

• Check whether the email was filtered as spam → junk filtering, dirty spam, and false positives
• Check routing and DNS → forwarding address, workspace, and custom email domain records
• Check sender authentication → SPF, DKIM, DMARC, and sender-side fixes
• Understand returned error messages → common inbound SMTP errors and what they mean
• Investigate replies that create new conversations → raw .eml files and examples to collect
• If emails still do not arrive → what to share with Crisp support
• Frequently Asked Questions → common edge cases before contacting support

Check whether the email was filtered as spam

The most common reason inbound emails do not appear in Crisp is that they are classified as spam. Crisp uses anti-spam protection to keep your Inbox safe from unwanted, spoofed, or suspicious emails, but legitimate emails can occasionally be flagged.

How Crisp classifies inbound spam

Crisp evaluates inbound emails and assigns a spam score. Depending on that score, the email may be accepted, moved away from the main inbox, or rejected completely.

Crisp uses two spam categories:

• Dirty → the spam score is above 6; the email is considered too unsafe and is rejected by Crisp internal anti-spam protection
• Junk → the spam score is between 3 and 6; the email can be blocked by the workspace junk filter and may be allowed by disabling that setting

In some cases, legitimate automated emails or lower-reputation sending infrastructure can be classified as junk. If the returned error shows a spam score below 6, test whether the email reaches Crisp without the junk filter.

Test the junk filter

To test whether the junk filter is blocking the email:

1. Go to Crisp
2. Open Settings → Email Settings → Email Behaviour
3. Disable Send emails that might be junk to the Spam inbox
4. Send a new test email to your Crisp Inbox address

Check routing and DNS

If the email is not filtered as spam, check whether it is being routed to the right Crisp workspace. Inbound emails only appear in Crisp when they are sent or forwarded to the correct Crisp Inbox address and, when applicable, through valid custom email domain records.

Verify the current Crisp Inbox address

You may be sending to an old Crisp address, a previous workspace, or another workspace owned by your team. In that case, the email can be routed somewhere else or rejected.

To verify the current inbound email address:

1. Go to Crisp
2. Open Settings → Workspace Settings → Setup & Integrations → Email
3. Compare the email address shown there with the address you are sending to
4. Update any forwarding rule, contact form, mailbox rule, or website integration that still uses the old address

Check custom email domain DNS records

If you use a Custom Email Domain, inbound emails require the Crisp-provided DNS records to stay valid. Emails can stop arriving if the Crisp MX record was removed, replaced, or mixed with an extra MX record pointing to another mail server.

What to check:

• MX record → it must match the value shown in your Crisp email setup
• Extra MX records → remove records that route inbound email to another server unless Crisp explicitly instructed you to keep them
• DNS propagation → wait for DNS changes to propagate before testing again
• Workspace subscription → make sure the workspace and its custom email domain are still active

Check sender authentication

Crisp verifies inbound emails to protect your Inbox against spoofing, phishing, and forged sender identities. The sender domain must authenticate the email with at least one valid SPF or DKIM signature. If both fail, Crisp rejects the email.

DMARC adds another rule layer. When a sender domain publishes a DMARC policy that requires rejection after authentication failure, Crisp must follow that policy and reject the email.

Ask the sender or their email administrator to check:

• SPF → the sending server is allowed to send on behalf of the sender domain
• DKIM → the message is signed correctly and the signature is still valid
• DMARC → the sender policy does not reject legitimate forwarded or automated messages
• Forwarding chain → forwarding providers are not breaking authentication before the email reaches Crisp

Understand returned error messages

When an inbound email is rejected, the sender usually receives a bounce or SMTP error. That message is useful because it names the failed check and often gives the exact condition to fix.

Common errors and what they mean:

• Got invalid email headers (From + To required) → required email headers are missing
• Got invalid email headers (From or To not acceptable) → the sender or recipient address is not valid or does not meet modern email standards
• Crisp session in address local part not recognized: EMAIL (invalid or does not exist) → the reply-to address was altered or points to a conversation that cannot be found
• Email text content is oversized → the email body is too large
• Email with same text already sent recently, please slow down → a duplicate message body was sent too quickly
• Sending address is currently rate-limited, please slow down → too many emails were sent in a short time from the same address
• From address does not exist or is invalid: EMAIL → the sender domain does not have valid MX records
• Email not authenticated. The sender must authenticate with at least one of SPF or DKIM: EMAIL → the sender domain failed both SPF and DKIM authentication
• Email origin could not be verified, you are possibly spoofing EMAIL → the sender domain DMARC policy requires rejection
• Your email has been classified as spam, and we dislike spam ERROR_NOTE, got score: SPAM_SCORE → the email was rejected by spam filtering
• Crisp session does not exist → the email was sent to a conversation reply address that no longer exists
• Crisp website is blocked → the workspace is restricted from receiving emails
• Crisp website does not exist → the workspace associated with the email address no longer exists
• Domain not bound to any Crisp website → the custom email domain is not associated with an active workspace
• Crisp email redirection plugin is disabled on Crisp website → inbound email handling is not active for the workspace
• We could not process the email at that time due to an internal error → contact Crisp support if the error repeats

Investigate replies that create new conversations

If an email reply arrives in Crisp as a new conversation instead of being attached to the existing one, the best way to investigate is to inspect the full raw email headers.

What to collect:

• Original .eml file → ask the sender to export the reply from their mailbox using an option such as Download original, View source, or Save as .eml
• Conversation examples → keep the original conversation and the new conversation created by the reply
• Sender details → include the sender mailbox provider and any forwarding tool used
• Reply address → confirm that the reply was sent to the exact address generated by Crisp for the conversation

If emails still do not arrive

If none of the checks above explains the issue, contact Crisp support with enough context to locate the delivery attempt. The more precise the details are, the faster the issue can be investigated.

Before contacting support, collect:

• Sender address → the exact email address that sent the message
• Recipient Crisp address → the Crisp Inbox address or custom email domain address used
• Approximate sending time → include the date, time, and timezone
• Bounce or SMTP error → forward the returned error received by the sender, if any
• Forwarding details → mention any mailbox, contact form, routing rule, or provider forwarding the email to Crisp
• Raw .eml file → include it when the issue concerns replies, missing headers, or conversations created in the wrong thread

Frequently Asked Questions

Still have questions which were not covered in this article? Here is a collection of the most frequently asked questions on this topic.

Why are automated emails not received in Crisp?

Automated emails can look suspicious to spam filters because they are often repetitive, sent in bulk, or sent from lower-reputation infrastructure. Ask the sender to check for returned error emails. If the spam score is in the Junk range, you can test whether disabling the junk filter lets those messages through.

Can I allow emails rejected as Dirty spam?

No. Emails classified as Dirty have a spam score above 6 and are rejected by Crisp internal anti-spam protection. Ask the sender to improve the email content, authentication, sending reputation, or sending infrastructure before testing again.

What should I check if there is no returned error?

Check the sender mailbox, forwarding rule, custom email domain DNS records, and the exact Crisp address being used. If you use an intermediate mailbox or forwarding provider, make sure it preserves authentication and forwards to the correct Crisp address.

Why does Crisp mention low reputation pools?

Low reputation pools relate to outbound emails sent from Crisp, not inbound emails received by Crisp. They are used to protect deliverability across shared sending infrastructure. To improve outbound deliverability, review your campaigns, transactional emails, sender reputation, and custom email domain setup.

For more details, read How to fight poor email deliverability and What are email reputation pools?.

Updated on: 03/05/2026