Limit to Sample Error Page

Hi,
Will you tell me how to set a ‘you have reached the limit’ page for people that click on the sample button one too many times? Right now it goes to an ugly ERROR page with a string of code and customers are not realizing that it is because they have clicked the sample button once too many times.

Thanks

https://ww.wp.xz.cn/plugins/woocommerce-sample/