Check the recipient address, spam folder, filtering rules and mailbox capacity. Ask the sender whether they received a delivery failure notification.
When requesting help, include the sending time and error message. Do not send passwords or confidential email content.
1. Narrow down the problem
- Check the mailbox in webmail too. If the message is there, investigate client synchronisation.
- Search Spam, Deleted Items and folders managed by rules.
- Check the mailbox quota and forwarding rules.
- Try sending from another external sender and request any delivery failure message.
2. Include these details when requesting help
- Sending timestamp and time zone.
- Sender and recipient addresses, limited to what is necessary.
- The delivery error code and relevant part of the message.
- Whether the issue affects all senders or only one address.
3. Choose the next step based on observations
| Result | What to investigate |
|---|---|
| Webmailben megvan, kliensben nincs | IMAP sync, subscribed folders, local filtering and account settings. |
| Email from one sender is missing | Incorrect addressing, sender bounce messages and recipient filtering. |
| All external email is missing | The domain's actual MX record, mailbox existence and receiving system. |
| Only messages with attachments are missing | Size limits and content filtering; use your own small test attachment. |
| Email arrives late | Temporary SMTP errors, queueing and log timestamps. |
4. Do not delete the account as your first troubleshooting step
Removing a client account can affect local folders and downloaded messages. First check webmail and back up the existing profile. For server log investigations, the message timestamp, route and delivery error are more useful than its full confidential content.
