[E-newsletter] E-newsletter problems

I suddenly found out the plugin isn't supported anymore. Several times I thought about canceling the subscription and now…

Anyway, I need help. Suddenly there is an issue when creating a new newsletter. Wehn selecting a theme we get "The theme directory "Disco" does not exist."

When clooning an existing newsletter the same problem. When using the same theme, changing the content isn't working anymore.

What to do? Hope you guys still give some support!

I deactivated the plugin and activated it again and downloaded the latest github version. But that didn't help. Also disabling all other plugins didn't help…