I am getting this error when i click on Buy Now button
Fatal error: Uncaught exception 'InvalidArgumentException' with message 'expected transaction id to be set' in /home/content/72/11576072/html/TME/wp-content/plugins/wp-braintree/braintree/lib/Braintree/Transaction.php:686 Stack trace: #0 /home/content/72/11576072/html/TME/wp-content/plugins/wp-braintree/braintree/lib/Braintree/Transaction.php(464): Braintree_Transaction::_validateId(NULL) #1 /home/content/72/11576072/html/TME/wp-content/plugins/wp-braintree/main.php(402): Braintree_Transaction::submitForSettlement(NULL) #2 [internal function]: wp_braintree->head_styles_scripts('') #3 /home/content/72/11576072/html/TME/wp-includes/plugin.php(429): call_user_func_array(Array, Array) #4 /home/content/72/11576072/html/TME/wp-includes/script-loader.php(846): do_action('wp_enqueue_scri...') #5 [internal function]: wp_enqueue_scripts('') #6 /home/content/72/11576072/html/TME/wp-includes/plugin.php(429): call_user_func_array('wp_enqueue_scri...', Array) #7 /home/content/72/11576072/html/TME/wp-includes/general-template.php(1634): in /home/content/72/11576072/html/TME/wp-content/plugins/wp-braintree/braintree/lib/Braintree/Transaction.php on line 686