Often errors when displaying

Dear developers,

i would love to use your plugin to promote some Amazon stuff, but often (even when caching is active) the items are just not displayed. I inserted the asa tag and sometimes it works and then i refresh the page with f5 and it does not work anymore. Do you have any idea how to fix this? my website is http://maca-wirkung.com/

fherz

https://wordpress.org/plugins/amazonsimpleadmin/