Error when sending template message in campaign: “Trying to access array offset on null”

We have encountered an error when attempting to send a template message in the campaign. The error message returned is: “Trying to access array offset on null”. This issue is affecting multiple users. We kindly request an analysis and resolution as soon as possible.

Would you please open a support ticket providing all details for which template and where it's getting error, so we can reproduce the issue. Then we can solve it properly. Thanks