Why are customer emails not creating tickets in Zoho Desk?
Because somewhere between the customer pressing send and a ticket appearing in your queue, one link in the chain has failed. The chain is longer than most people realise: the customer’s mail server, your mail server, a forwarding rule, Desk’s inbound processing, its spam filter and block list, department mapping, then threading logic that decides whether the email becomes a new ticket at all.
A failure at any of those points looks identical from the outside: the customer gets no bounce, your agents see nothing and there’s no error to read.
That makes this a genuine outage rather than a quirk. A broken workflow annoys your own team; a broken email channel means customers are writing to you and being ignored, with no acknowledgement email to tell them anything is wrong. Work through the six causes below in order - it’s the sequence we use ourselves and it usually finds the fault within the first two.
1. Has the forwarding rule at your mail server broken?
Start here. It’s the most common cause by a distance, particularly on Microsoft 365 and Exchange.
Zoho Desk does not log into your mailbox. Your mail server receives the message at support@yourcompany.com, then a forwarding rule passes it on to a Desk address that looks like support@yourcompany.zohodesk.com (or .eu on the European data centre). If that forward stops, Desk hears nothing. Your mailbox still fills up normally, so the problem hides in plain sight.
Things that break the forward:
- Microsoft’s automatic forwarding block. Microsoft 365 disables automatic external forwarding by default through the outbound spam policy. A tenant change, a security review or a new baseline policy can switch off a forward that worked for years.
- Connector or transport rule changes. Admins tidy up mail flow rules without realising one of them feeds the helpdesk.
- Mailbox changes. The shared mailbox gets migrated, relicensed or has its rules wiped during a password reset.
To check, open the Exchange admin centre, go to Mail flow → Message trace and trace a recent message sent to your support address. You want to see two hops: delivery into your tenant, then a forward out to the zohodesk.com address. If the second hop is missing or shows as blocked, you’ve found your fault.
The fix depends on how the forward was built. If it’s an inbox rule on the mailbox, it sits under Microsoft’s auto-forward restriction; either enable external forwarding for that mailbox in the anti-spam outbound policy (Microsoft Defender portal → Policies & rules → Threat policies → Anti-spam) or, better, replace it with an Exchange mail flow rule that redirects messages to the Desk address. Transport-level redirects are not subject to the automatic forwarding block and they survive mailbox changes.
2. Is Desk silently blocking the sender?
Zoho Desk keeps a block list and it is easy to populate by accident. When an agent marks a ticket as spam, Desk offers to block the sender’s address at the same time. Tick that box on the wrong ticket and every future email from that customer vanishes. Block a domain and you can lose an entire company’s correspondence.
There is no bounce, no notification, no entry in any queue. This is the sneakiest cause on the list, which is why it comes second despite being rarer than a broken forward.
Go to Setup → Channels → Email and open the Blocked List. Review every entry, remove anything that should not be there, then have a quiet word with the team about that tickbox.
3. Is Desk’s own spam filter holding the tickets?
Desk runs spam detection on inbound email, entirely separate from whatever filtering your mail server does. Messages it suspects still become tickets, but they land in the Spam view of the department and the default views never show them.
Open the ticket list, switch to the Spam view in each department and look for genuine customer emails. Mark any real ones as Not Spam - this restores the ticket and trains the filter against repeating the mistake. Senders with no previous contact record, marketing-flavoured subject lines or failing authentication on their own domain are the usual victims.
Deliverability cuts both ways, incidentally. If customers also complain that your replies land in their junk folder, that’s the mirror-image problem, covered in our guide to Zoho CRM emails going to spam. The same SPF and DKIM hygiene applies.
4. Has the email channel verification lapsed?
Every external support address you add to Desk must be verified before Desk will process its mail and that verified status is not guaranteed to last forever. Domain moves, mailbox migrations and changes to the From address can knock a channel back to unverified, at which point inbound processing stops without ceremony.
Check Setup → Channels → Email and look at the status against each support address. Anything showing as unverified or pending needs the verification redone; Desk will walk you through sending the confirmation again. While you’re on that screen, confirm the From address still exists as a real mailbox. Replies sent from a deleted alias bounce, which earns your domain a reputation problem on top of the original outage.
5. Is the address mapped to the wrong department?
Sometimes the tickets are being created perfectly. They’re just being created somewhere nobody looks.
Each support address in Desk maps to exactly one department. If someone re-pointed an address during a restructure, or the target department was deactivated, new tickets pile up in a queue with no agents watching it. The symptom is identical to total failure unless you search globally.
Two quick checks. First, search Desk for the sender’s email address across all departments. Second, review the address-to-department mapping under Setup → Channels → Email and confirm each address points where you think it does. This one bites hardest after reorganisations - we find it regularly when taking over an existing helpdesk in our Zoho Desk work.
6. Are threading rules swallowing new requests into old tickets?
Desk decides whether an inbound email is a new ticket or a reply to an existing one using hidden message headers and the ticket reference in the subject line. The logic is sensible until a customer does the natural thing: digs out your last email from six months ago and replies to it with a completely new problem.
Desk appends that message to the original ticket. If the ticket is closed, the reply sits on a closed record that no open-ticket view will ever surface. From the agent’s side, the customer never wrote in. From the customer’s side, you’re ignoring them.
To check, open the contact’s record in Desk and review their full ticket history, closed tickets included. If you find new requests buried in old threads, two fixes help: configure how Desk handles replies to closed tickets so they reopen visibly and teach agents the split thread action, which breaks a reply out into its own ticket in two clicks.
How do I test the email-to-ticket pipeline end to end?
Once you’ve fixed the suspected cause, prove the whole chain works. The test takes five minutes:
- Send from an outside address. Use a personal account on a different domain. Give it a unique subject line (“Desk pipeline test 0611”) so threading can’t swallow it.
- Confirm your mailbox received it. If the message never reached support@yourcompany.com, the fault is upstream of Desk entirely - MX records or your mail provider.
- Trace the forward. Run a message trace in Exchange and confirm the message left for the zohodesk.com address.
- Search Desk for the subject line across all departments. Check the open queue first, then the Spam view, then the Blocked List.
- Check the acknowledgement. If your auto-response arrived back at the test address, the full loop is healthy.
If the test passes but one specific customer still can’t raise tickets, you’re back to causes 2 and 6: their address is blocked or their emails are threading into an old ticket.
Repeat the test after any Microsoft 365 admin change. A broken forward gives you no error, so it’s worth sending a quick test email once a month.
Quick diagnostic checklist
- Message trace at the mail server: did the forward to zohodesk.com actually leave?
- Blocked List under Setup → Channels → Email: is the sender or their domain on it?
- Spam view in each department: are the missing tickets sitting there?
- Channel verification: does every support address show as verified?
- Department mapping: search the sender’s address across all departments.
- Threading: check the contact’s closed tickets for buried new requests.
- End-to-end test email from an external address with a unique subject line.
A dead support inbox won’t wait for a project plan
Every hour this stays broken, more customer emails go missing. If you’ve worked through the list and tickets still aren’t arriving - or you don’t have admin access to Exchange and Desk to check in the first place - our emergency Zoho developer service puts a senior developer on the problem within 30 minutes during UK business hours, with published pricing so you know the cost before you call.
For the longer term, a Zoho support plan means someone is watching channels like this and failures get caught early. Either way, get in touch for a free discovery consultation and we’ll tell you whether this is a ten-minute fix or something deeper in your mail flow.