Licensing Issues

Dear team,

I am your premium version users and last 2-3 months our customers cannot match the license. After that we found this error Deprecated: strpos(): Passing null to parameter #1 ($haystack) of type string is deprecated in?/home/dh_ejpkvh/amadercode.com/wp-content/plugins/woocommerce-license-keys-extended/vendor/10quality/wp-query-builder/src/QueryBuilder.php?on line?872

our customers are not able to match the license. Please solve it.

The page I need help with: [log in to see the link]