Google Apps Script lost access rights - email

Question

I have a Google Sheets script that emails a notification to a group of people when a form is submitted. It worked beautifully for months. Now it seems to have lost the access rights to send the emails. November 6, 2015 was the last time responses were submitted and successfully emailed. No more responses were submitted until yesterday (Sept 21, 2016) and it no longer has rights to send email. I verified that it is not listed in my Google account's security section under my "apps connected to your account".
I tried to re-authorize it by deleting all the triggers, saving and closing out the script. Then I reopened it and added the triggers back in. It didn't ask for a new authorization, but it still won't send emails.
Does anyone know why it might lose access rights? Does it get removed if it's not used periodically?
How do I force it to refresh/renew rights? Or do I just have to delete the script entirely and recreate a fresh copy?
This is just one of many similar scripts that I have so, I need to figure out how to make them work (and keep them working). Searching around I couldn't find anything except how to intentionally revoke access rights.
Here is my code so you can see what it's trying to do (I'm testing it with just my email address right now). I will admit I don't know a lot about programming scripts, so it may not be very pretty.
Thanks for any help!
function sendFormByEmail(e)
{
// Remember to replace this email address with your own email address
var email = "bjwarneke#gmail.com";
var quiz = "02.8-JLOT-D Drop-In";
var filename = "02-JLOT Exam Grading Instructions";
var s = SpreadsheetApp.getActiveSheet();
var headers = s.getRange(1,1,1,s.getLastColumn()).getValues()[0];
var message = "Time for someone to go grade a quiz from me!" + "<br>";
var replyto = e.namedValues[headers[1]].toString();
var subject = 'Quiz: ' + replyto;
//message += headers[1] + ': '+ e.namedValues[headers[1]].toString() + "\n";
//message += headers[0] + ': '+ e.namedValues[headers[0]].toString() + "\n";
message += headers[1] + ': '+ e.namedValues[headers[1]].toString() + "<br>";
message += headers[0] + ': '+ e.namedValues[headers[0]].toString() + "<br><br>";
message += quiz + "<br>";
message += ''+filename+'<br>';
// The variable e holds all the form values in an array.
// Loop through the array and append values to the body.
//for(var i in headers)
//message += headers[i] + ': '+ e.namedValues[headers[i]].toString() + "\n\n";
// Insert variables from the spreadsheet into the subject.
// In this case, I wanted the new hire's name and start date as part of the
// email subject. These are the 3rd and 16th columns in my form.
// This creates an email subject like "New Hire: Jane Doe - starts 4/23/2013"
//subject += e.namedValues[headers[2]].toString() + " - starts " + e.namedValues[headers[15]].toString();
// Send the email
MailApp.sendEmail(email, subject, message, {htmlBody:message, name:"Quiz", replyTo:replyto});
// Based off of a script originally posted by Amit Agarwal - www.labnol.org
// Credit to Henrique Abreu for fixing the sort order
}

Answer 1

Do you have a Gmail account associated with your Google Account? The MailApp service will only work if you have Gmail enabled for your account.