Unknown cause error "Exception: Form data could not be retrieved during Google form submission.Please try again in a few moments."

We are currently using Google form submission as a trigger to run a function of gas.
I usually use it without any problems, but recently there have been about three triggers, and I don't know the cause of the error.Basically, it's going well, I don't know the conditions under which the error occurs, and it's hard to check.

So if anyone knows, please let me know.
Also, when I searched the error statement, I didn't get caught at all, so if anyone has seen a similar error, please let me know.

US>Error statement
Exception—Failed to retrieve form data.Please try again in a few moments.

The affected codes are as follows:There should be no problem with the abbreviations.

function notify(e){
  // Omitted
varitemResponses=e.response.getItemResponses(); // Error on this line
 // Omitted
}

It says that the data on the form could not be retrieved, so I thought it might be a network error, so I was watching the situation for a while, but recently three cases suddenly occurred, so I asked you a question.Thank you for your cooperation.