already registered

If I am already subscribed to the newsletter, and I register again, I do not receive any communication.
Is it possible to provide a popup message or an e-mail warning of this exception?

Do you want to show popup window if customer is a newsubscriber again?
It's not a good idea.

Support wrote:
No I don't wont this.

But what happens if I am a user already registered and I write again my email in the subscription popup?
I don't receive notification...
It is better to show a popup that notify "Sorry your email is already registred"

If you are registered customer
1. Plugin checks if you are a newssubscriber and if YES than plugin doesn't show popup window
if NO than plugin shows popup window.

Please check this logic.
P.S.
Pay attention to cookies.

Support wrote:

I can be a user already registered for the newsletter.
But how does the plugin behave if I access the website without being logged in?
if I access from a new device where the "foxnetsoft.newslettersubscription.popupwindow" cookie does not exist or has already been deleted? The plugin show popup window and I can insert my email...
But I am already registered.. and I receive again a coupon code.
It is importa to check in the newsletter table if my email is already present, and send an email with the notification.

No, you will not be able to get the second coupon code.
You entered your email second time from the new devise.
Plugin checks this email in the new subscriber list and if you are a subscriber than plugin will show you Thank You page but plugin will not send you anything.

Support wrote:

OK I know that I don't receive a second coupon code,
but it would be better if I received a notification that I am already registered (via popup or email). The Thank you message is the same for registered and not registered

I agree with you.
I did the new release now.
Download the new release, replace all files, restart your store.
Open plugin configure page and try.
Write me about result.

Support wrote:
Great !
It is exactly what i need!
I downloaded and installed it.
The result is OK!!

Can you write a review about our support?
https://www.nopcommerce.com/popup-newsletter-subscription-foxnetsoftcom

Thank you.