Error loading thumbnail with plugins

Hi, I am a happy Easyengine user for years and using the latest version of Easyengine 3.7.4 and having troubles with different plugins that try to load a generated thumbnail from an user uploaded image.

Image is successfully generated on server and I can view/download it in the browser, but with scripts it is not loaded. Since it is happening with two different plugins I think it is a server setting… anybody knows how to fix this?

This is fixed and can be closed/deleted. Problem was bug in the theme.