cant translate “You can add a maximum of %1….

Hi, I am not able to set the text line “You can add a maximum of 60 Booklet BVMW’s to your cart. You already have 60.” into german.

I′ve tried it with Loco Translate, no result is visible in the frontend.
I′ve tried it by editing the files “max-quantity-for-wc-shops.php” and also in file “max-quantity-for-wc-shops.pot” and uploaded it via FTP.
Nothing worked out. No german text showing up in the frontend.
Cache cleared a thousand times.

Does anybody knows, where I can change the text
“You can add a maximum of %1$s %2$s’s to %3$s. You already have %4$s.”

Thanks a lot, nice greetings Sandra