Same issue here. I am getting an “Internal error” when trying to checkout. The log begins as follows:
2021-06-18T08:41:07+00:00 CRITICAL Uncaught TypeError: Unsupported operand types: int * string in (...)/wp-content/plugins/woocommerce-sendinblue-newsletter-subscription/woocommerce-sendinblue.php:740
Which is due to the PHP version as well…
