Newsletter Plugin Buttons Not translate to german

hello I have a problem with the translation on a part of a plugin.

It is the newsletter plugin, https://www.thenewsletterplugin.com/ticket/newsletter

On my page https://trading-evolution.de/trading-community/trading-ideen-chartletter/

At the bottom, the 2 buttons are simply not translated, although it is entered in the translation file.

The page I need help with: [log in to see the link]