When user checks "Subscribe to Newsletter", his email is not added to the VSETH system.
Solution:
It is already possible to list only the users who checked that they want the newsletter. Just add a feature in the dropdown menu to download list of all emails.
Then I can easily import them to the VSETH newsletter system.
roggnroll
commented
6 years ago 
Problem:
When user checks "Subscribe to Newsletter", his email is not added to the VSETH system.
Solution:
It is already possible to list only the users who checked that they want the newsletter. Just add a feature in the dropdown menu to download list of all emails. Then I can easily import them to the VSETH newsletter system.