Shopkeeper Version: 1.68
Spigot Version: I have Thermos

I want to test Villgaer and when im clicking anything then trade gui is closing

Modded servers other than CB / Spigot are not supported.
However, in the past I was able to resolve this specific issue by disabling a minor check inside the code. See #538

A version of shopkeepers with this check disabled can be found here: www.blablubbabc.de/daten/Shopkeepers-no_ui_check.jar

Since Thermos seems to be a variant of Cauldron and the described issue seems to match the issue of the linked ticket, check if this version of shopkeepers works for you as well. If it does not, you are out of luck.

works thx