This error will occur in the API where the upload parameter requires encryption of sensitive information. Please refer to Declaring the platform certificate used in encryption When the certificate serial number is wrong or does not correspond to the platform certificate of the requested merchant ID, WeChat Pay will return the error message in the question. Please check: ○ Whether the certificate used for encryption is a WeChat Pay platform certificate. A wrong merchant certificate may cause this error. ○ Check whether the certificate is the WeChat Pay platform certificate that corresponds to the requesting merchant, or if the platform certificate of another merchant ID was used. ○ Check whether the merchant certificate has expired. Follow the instructions to check whether the certificate has expired, and update then deploy the new certificate. |