I have translated the Success message says: "Thank you..."
You can see it here https://premium.wpmudev.org/translate/projects/forminator/he/default/?filters%5Bterm%5D=Thank+you&filters%5Buser_login%5D=&filters%5Bstatus%5D=current_or_waiting_or_fuzzy_or_untranslated&filter=Filter&sort%5Bby%5D=priority&sort%5Bhow%5D=desc
I have downloaded and uploaded the files. All other translations work perfect. Only the SUCCESS message is shown in English anyway whatever i do.