I faced the issue of mails not getting sent from the Email module which had an SSIS Package. I imported the troubled emails to my dev machine and debugged to find out that the SSIS has a limitation with the expression. A string expression should be less than 4000 characters!
So some of my automated emails has a messagebody > 4000, hence the issue.
SSIS allows direct entry of MessageBody through variable.
So I solved the problem by making SSIS read the meesagebody from a variable.
