I set up our braintree account a couple of weeks ago, and are approved to begin transactions. I've followed all of the steps in the Magento user guide. I'm trying to do a test purchase, though whenever I try to submit the payment, I get an error "An error occurred on the server. Please try to place the order again."
In the error.log I get the following:
[2017-09-12 17:40:47] main.CRITICAL: Broken reference: No element found with ID 'checkout.header.wrapper'.   [2017-09-12 17:42:33] main.CRITICAL: Braintree error response.   [2017-09-12 17:42:33] main.CRITICAL: Wrong transaction status  
- Ubuntu 16.04
- Apache 2.4
- Mysql 5.7
- PHP 7
- Magento 2.1.8
I've searched and searched for an answer, and tried implementing some solutions, though the error is still occurring, what can I do next?