# Questions about ZNS
## Question 1. Common Errors When Sending ZNS Messages
To successfully launch a ZNS messaging campaign to customers, it is crucial to ensure that the content and setup of the Zalo ZNS message are valid. However, errors can still occur. Below is a list of common error messages and their descriptions to help businesses identify and resolve issues more effectively, thereby improving service quality and driving business growth.
| **ERROR DESCRIPTION** | **DETAILS** |
| ---------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Success | *Message sent successfully* |
| Unknown error | *An unidentified error occurred. Please try again later* |
| Appllication invalid | *The ZNS-sending application is invalid* |
| Application not existed | *The application does not exist* |
| Application not activated | *The application has not been activated* |
| App secret key invalid | *The application’s secret key is invalid* |
| Application not link to any OA | *The application is not linked to any Official Account (OA)* |
| Method unsupported | *The method is not supported* |
| Message ID invalid | *The message ID is invalid* |
| Phone number invalid | *The phone number is invalid* |
| Template ID invalid | *The ZNS template ID is invalid* |
| Zalo version unsupported | *The user’s Zalo app version is not supported. They need to update to the latest version* |
| Template data empty | *The ZNS template has no data* |
| Template data invalid | *The ZNS template content is invalid* |
| QR code cannot be generated | *Unable to generate QR code. Please check again* |
| Button invalid | *The button is invalid* |
| User is inactive, or reject the message, or using an outdated Zalo version, or other internal errors | *The user did not receive the ZNS message due to reasons such as account status, ZNS reception settings, outdated app version, or other internal errors* |
| Out of quota | *ZNS account has insufficient balance* |
| Text invalid | *Message content is invalid* |
| OA or App does not have permission to access this template | *The OA or app does not have permission to use this template* |
| Zalo account not existed | *The Zalo account does not exist or has been deactivated* |
| Account can not receive message | *The account cannot receive ZNS messages* |
| OA does not have permission to use this feature | *The OA has not been granted access to this feature* |
| Body data empty | *The ZNS template has no content* |
| Body format invalid | *The request body is not in valid JSON format* |
| RSA message decoded failed | *Failed to decode RSA message content* |
| Access token invalid | *Access token is invalid* |
| Official Account ID invalid | *Official Account ID is invalid* |
| Out of quota (development mode) | *Insufficient balance in development mode* |
| Test template messages can only be sent to admin | *Test messages can only be sent to admin users* |
| Encoding key not existed | *Encoding key does not exist* |
| RSA key cannot be generated | *RSA key generation failed. Please try again later* |
| Maximum character limit exceeded | *NS message content exceeds the character limit* |
| ZNS template not approved | *The ZNS template has not been approved* |
| Parameter invalid | *Invalid parameters provided* |
| This template cannot be sent at night (10PM-6AM) | *This ZNS template cannot be sent between 10PM and 6AM* |
| User has not responded to opt-in inquiry | *The user has not responded to the ZNS opt-in request* |
| No permission to send ZNS (not verified, in free subscription plan) | *The OA does not have permission to send ZNS (not verified or using a free plan)* |
| ZCA association required | *ZCA integration is required to use this feature* |
| ZCA charge failure | *ZCA payment failed (e.g., insufficient wallet balance)* |
| App does not have permission to access this feature | *The ZNS app is not authorized to use this feature* |
| User refused to receive this type of ZNS | *The user declined to receive this type of ZNS message* |
| No permission to send follow-up to this user | *OA is not permitted to send follow-up ZNS messages to this user* |
| User refused to receive ZNS | *The user opted out of receiving ZNS messages from the OA* |
| RSA key not exist | *RSA key does not exist; please call the API to generate one* |
| RSA key already existed | *RSA key already exists; please call the API to retrieve it* |
| ZNS daily quota exceeded | *OA has exceeded the daily ZNS sending limit* |
| OA does not have permission to send this type of ZNS | *OA is not permitted to send this type of ZNS message* |
| Template disabled due to low quality | *This ZNS template has been disabled due to poor performance/quality* |
| Tempalate daily quota exceeded | *The template has exceeded its daily sending limit* |
| OA exceeded the limit of sending ZNS follow-ups to this user for the month. | *OA has reached the monthly follow-up ZNS limit for this user* |
| ZNS journey token missing | *ZNS journey token not found* |
| ZNS journey token invalid | *ZNS journey token is invalid* |
| ZNS journey token expired | *ZNS journey token has expired* |
| Not an E2EE template | *The template is not an E2EE-type ZNS* |
| Get E2EE key failed | *Failed to retrieve E2EE key* |
| Template is miss a data holder\* | *Template is missing required data fields* |
When the ZNS shows a failure status, please click the icon  to check the reason for the failure.
* For the failure reason **"Template is missing a data holder"**, click the icon  within the message template content to check for any missing data information.
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