Allow only selected account to submit a Google Form - google-apps-script

Question

Is there a way (Apps Script maybe?) to inform google forms submitter that his submission will not be gaethered because the form is restricted to selected google accounts?
My try looked like this, but it has 2 problems :
-it is accepting answers submitted from people other than verified and verified2 (no idea how to add that)
-it only displays my custom message if someone tries to submit second answer
function onFormSubmit(e){
var af = FormApp.getActiveForm();
var defaultClosedFor = af.getCustomClosedFormMessage();
af.setCustomClosedFormMessage("You are not using an account with submission access. Please log in to account with correct authorization");
var responses=af.getResponses();
if(responses[responses.length-1].getRespondentEmail()=="verified#gmail.com" ||
responses[responses.length-1].getRespondentEmail()=="verified2#gmail.com"
){
af.setCustomClosedFormMessage(defaultClosedFor);
}
}

Answer 1

I see multiple problems with the code:
Custom Closed Form Messages are only displayed when the form is closed for responses manually or the form only allows one response per email account.
Email addresses are not collected on the form. It has to be enabled manually on the Form settings.
Solution:
Enable Collect Email Addresses option on Google Form Settings:
Use setConfirmationMessage() to display custom messages depending on the entered email when the form is submitted.
Sample code:
function createTrigger() {
var form = FormApp.openById('****your-form-id****');
ScriptApp.newTrigger('validateForm')
.forForm(form)
.onFormSubmit()
.create();
}
function validateForm(e){
var af = FormApp.getActiveForm();
af.setCollectEmail(true);
var responses=af.getResponses();
var defaultConfirm = "Your response has been recorded.";
var rejectMessage = "You are not using an account with submission access. Please log in to account with correct authorization.";
if(responses[responses.length-1].getRespondentEmail()=="verified#gmail.com" ||
responses[responses.length-1].getRespondentEmail()=="verified2#gmail.com")
{
af.setConfirmationMessage(defaultConfirm);
}
else {
af.setConfirmationMessage(rejectMessage);
af.deleteResponse(responses[responses.length-1].getId());
}
}
Note: Please run createTrigger() first manually in GAS to create the on form submit trigger.