Auto Update failed

Dear Sir or Madame,

I installed the plugin, nearly everything works fine.
I tried “Hello! Would you like to receive automatic update? Please activate your copy of WooCommerce Product Variations Swatches Premium” if I do so, and click on get key a second window opens and the key shows up at the right position, before I can click save, it disappears sudently.
Can you please help me

Kind regards
Lukas