> ## Documentation Index > Fetch the complete documentation index at: https://docs.mailchannels.com/llms.txt > Use this file to discover all available pages before exploring further. # Troubleshooting > Diagnose and fix common MailChannels Email API for WHMCS problems: provisioning failures, error messages, drift, and customer sending issues. ## Where to look 1. **Addons > MailChannels Email API > Operation history**. The last 20 operations with outcome, error code, and MailChannels request ID. 2. **Utilities > Module Queue** in WHMCS. Failed module commands with the sanitized error message returned to WHMCS. 3. The `mod_mailchannels_email_api_operations` table, for history older than the last 20 entries. 4. **WHMCS Activity Log**, for module command invocations. The plugin never writes secrets to any of these locations, so you can share their contents with MailChannels support along with the request ID. ## Error messages The plugin maps MailChannels API responses to fixed messages. | Message | HTTP status | What to do | | - | - | - | | MailChannels rejected the parent API key. | 401 | The stored parent key is invalid or revoked. [Reconnect](/plugins/whmcs/connect-parent-account) with a new key. | | The parent API key cannot manage this MailChannels resource. | 403 | The key lacks permission, or belongs to a sub-account. Use a parent-account key. | | The MailChannels resource was not found. | 404 | The sub-account or credential was deleted outside WHMCS. Run **Reconcile now** to identify drift. | | The MailChannels resource already exists. | 409 | A sub-account with this handle exists but could not be found in the list. Retry. If it persists, contact support with the request ID. | | MailChannels rate-limited the operation. | 429 | Wait and retry. Avoid applying plan changes to many services at once during peak hours. | | MailChannels could not complete the operation. | 5xx | A MailChannels-side error. Retry later. Check [System Status](https://status.mailchannels.net/). | | The MailChannels API operation failed. | Other | A transport or unexpected error. Check outbound HTTPS connectivity from the WHMCS server to `api.mailchannels.net`. | ### Plugin messages | Message | Cause | Fix | | - | - | - | | Connect a MailChannels parent account in the addon module before provisioning. | No parent key is stored. | [Connect the parent account](/plugins/whmcs/connect-parent-account). | | Sends per billing period must be a positive integer. | The product's first module setting is empty, zero, negative, or not a whole number. | Edit the product's **Module Settings** and enter a positive integer. | | Credential mode must be api, smtp, or both. | The product's second module setting has an unexpected value. | Choose a value from the dropdown and save. | | The new send limit is below current-period usage; the package change was not applied. | A downgrade would put the customer over their new limit. | Wait for the billing period to reset, or choose a higher limit. | | Another MailChannels operation is already running for this service. | Two operations overlapped and the second waited more than 20 seconds. | Retry after the first finishes. | | MailChannels service state was not found. | A lifecycle command ran on a service that was never provisioned. | Run **Create** first. | | The bundled MailChannels SDK runtime is missing. Reinstall the complete module release. | The `vendor-scoped` directory is missing or incomplete. | Re-copy `modules/servers/mailchannels_email_api` from the repository or your release ZIP. | | Non-HTTPS MailChannels API override is disabled outside the development harness. | `MAILCHANNELS_WHMCS_API_BASE_URL` points at a non-HTTPS URL. | Remove the override. See [API endpoint](/plugins/whmcs/security#api-endpoint). | | Credential creation had an ambiguous outcome and multiple new provider IDs were found. Administrator recovery is required. | A timeout during credential creation left more than one unknown credential. | Open the sub-account in the MailChannels Console, remove credentials WHMCS does not list, then retry. | | WHMCS could not process encrypted module data. | The WHMCS encryption API failed, usually because the encryption hash changed. | Restore the hash, or reconnect the parent key and have customers rotate credentials. | ## Provisioning stays in "provisioning" The service row exists but never reached `active`. 1. Check the operation history for the `create` failure and its error code. 2. Fix the cause using the tables above. 3. Retry from **Recovery and reconciliation > Retry provisioning**, or run **Create** from the service's Module Commands. Retrying is safe. The plugin reuses the sub-account if it already exists and only creates credentials the service still lacks. ## Customer cannot send Have the customer reveal the credential again from the client area and compare it with what their application uses. If they rotated recently, make sure they confirmed the rotation and updated every application that uses the old credential. For SMTP, the username must be the sub-account handle shown on the page, not the customer's email address. Ask the customer to use **Check domain** on an API plan, or check the domain yourself with the [check-domain tool](https://dash.mailchannels.com/domain-health). The `_mailchannels` TXT record must authorize the account that sends. See [Domain Lockdown](/email-api/domain-lockdown). The sending domain has no valid A or MX record. The customer must add one. See [Troubleshooting the Email API](/email-api/troubleshooting). Compare the client area usage with the plan limit. If the customer is under their own limit but sending is blocked, check the **Shared parent ceiling** card. When the parent account reaches its limit, every sub-account is blocked until the next billing period. WHMCS shows the service as suspended in the client area and hides the management panel. Unsuspend the service in WHMCS. If WHMCS shows it active but MailChannels has it disabled, reconciliation reports `remote_lifecycle_drift`. Run **Unsuspend** from Module Commands to re-apply the WHMCS state. Messages sent over SMTP do not produce MailChannels delivery webhooks and are not DKIM-signed by MailChannels. This is expected. Customers who need either should send through the API. See [Email API vs SMTP](/email-api/email-api-vs-smtp). ## Reconciliation reports drift See [Fix drift](/plugins/whmcs/capacity-and-reconciliation#fix-drift) for the meaning of each drift code and the module command that corrects it. ## Client area shows "Usage: Unavailable" or an error The page refreshes usage from MailChannels when the 15-minute cache expires. If MailChannels cannot be reached, the page shows the last cached values and a sanitized error. Check connectivity from the WHMCS server and the parent key status on the addon page. ## Contact support When you contact [MailChannels support](https://support.mailchannels.com/hc/en-us/requests/new), include: * The plugin version, WHMCS version, and PHP version. * The operation, outcome, error code, and request ID from the operation history. * The sub-account handle. Never include credentials. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.