Error with aws

hi admin, i just want ask how to solve this problem with this error :

Notice: Undefined index: Keywords in /home/u921447602/public_html/wp-content/plugins/amazon-product-in-a-post-plugin/inc/amazon-product-in-a-post-aws-signed-request.php on line 850

Notice: Undefined index: SearchIndex in /home/u921447602/public_html/wp-content/plugins/amazon-product-in-a-post-plugin/inc/amazon-product-in-a-post-aws-signed-request.php on line 850

you can go here to see this error : http://onlinestore99.16mb.com/review/danby11/

https://ww.wp.xz.cn/plugins/amazon-product-in-a-post-plugin/