Google Apps Script google.script.run.withSuccessHandler not working

I have 2 calls to google.script.run.withSuccessHandler that happen one after the other and when I try to combine the two it doesn't work. Here's the code that works, with all the main reasons involved.

//These are in a javascript function which executes when a submit button is clicked.
google.script.run.withSuccessHandler(updateOutput).processForm(frmData);
google.script.run.withSuccessHandler(returnMessage).sendEmail(theData, titles);

//server functions
function processForm(theForm) {
  try{
    var fileBlob1 = theForm.resumeFile;

    var fldrSssn = DriveApp.getFolderById('My Folder ID');
    fldrSssn.createFile(fileBlob1);

    return 'good';
  }catch(e) {

  }//End catch
}

function sendEmail(arr, titles) {
  try {
         //This function sends an email and edits a spreadsheet. Nothing is affected
       return 'Request Submitted';
  }
}

      

        
        
        
      

    

But when I try to combine the two, the program recognizes that the submit button is clicked, but it doesn't navigate past the google.script.run.withSuccessHandler command.

//google.script.run.withSuccessHandler(updateOutput).processForm(frmData);
google.script.run.withSuccessHandler(returnMessage).sendEmail(theData, titles, frmData);



function sendEmail(arr, titles, theForm) {
  try {

    //Uploads the files
    var fileBlob1 = theForm.resumeFile;

    var fldrSssn = DriveApp.getFolderById('My Folder ID');
    fldrSssn.createFile(fileBlob1);
    var url1;
    //Contains the rest of the code for sending an email and editing a spreadsheet.


    return 'Request Submitted';
  }
}

      

        
        
        
      

    

This does not work. Does anyone know why this fails? Functions that are called when the first functions succeed will only display a pop-up informing the user that their response has been sent.