translation problems

Hi,

Im having difficulties to make my translation to work!

I have tried to name my files like this;

gift-cards-for-woocommerce_da_DK.pot
gift-cards-for-woocommerce-da_DK.pot
gift-cards-for-woocommerce-master-da_DK.pot
gift-cards-for-woocommerce.pot
da_DK.pot

And saved the pot. and .mo file in /languages

But nothing happens on my site with the translations…
Is it wrong file name or?

Please can u advice me

Best regards,

Nhat

https://www.ads-software.com/plugins/gift-cards-for-woocommerce/