Fix Square WooCommerce Payment Failure

My WordPress site was taking credit card payments through Square with no problems, and it suddenly stopped. I didn’t make any major changes to the site that I know of. I need an experienced WordPress/WooCommerce developer to find the cause and fix it... (Budget: $10 - $30 USD, Jobs: HTML, Payment Gateway Integration, Payment Processing, PHP, Website Development, Website Optimization, WooCommerce, WordPress)