Newsletter

Hello. I have a problem with completing the newsletter. If I use an email for the first time, it is added to the newsletter and gets a message about success. The URL in such a case is / subscriber / success / status / 1 / params // isSubscriptionSuccess / 1. However, if I use this email for the second time, the newsletter form simply loads again. The URL in this case is subscriber / index / status / 2 / params // isSubscriptionSucces /. I wanted to find out where the information about sent emails is stored and where is the view and the controller of the newsletter. Possibly where you can perform configurations in the backend because in content-> forms there is no newsletter. Thanks.

Never mind. It is made by plugin. I will delete this post form moment.