The workflow does not send emails

The workflow has been working fine for more than a year but now it is not mailing the reports. When I manually test the workflow it does not send anything either and in the browser console it shows the following error: Uncaught SyntaxError: Unexpected end of JSON input

The problem seemed to come from the fact that the message body template is made up of a series of tables and the payload becomes perhaps too large; but now it does not send the emails it does not matter if you put the template or not, it has a table or not, it only tells me that the payload is too large and it does not execute the action.

It doesn’t make any sense because I have other apps for other clients with templates in the messages and tables in the templates working fine. What could be the problem?

Please contact for help with this.