Alerting email error : message file too big

I have this alerting query which will look and validate last 30min data and trigger an alert if the threshold exceed.
I’m using Infinity data source to fetch the metric from the endpoint. basically the endpoint returns data for last 24hr.

When the alert is triggered it is not sending out the email due to the below error.

I want to understand what is being sent on the email can we look at it in some way? or is it sending all the 24hr metric which is causing the size to exceed ? if yes, is there an way to not include that metric in email and basically add a two line message.

Can anyone kindly help me with this?