Greetings everyone.  Let me first apologize if this has been successfully covered in another thread.  I've been combing through forums all day and have found very little to help me solve this issue.  As of May 2017 (last successfully documented customer transaction), my site hasn't been able to complete transactions using Paypal.  I'm using Drupal 7 (7.56) w/ Drupal Commerce module and Paypal (commerce_paypal_wps) module version: 7.x-2.4.  When users reach the confirmation screen asking them to verify their information, they can then click 'checkout' button at which point they should be redirected to Paypal's login/confirmation screen.  Unfortunately, the Paypal login/confirmation redirect doesn't render and is instead replaced with the following error:

```BAD_INPUT_ERROR - Things don't appear to be working at the moment. Please try again later.```

I've tried a number of possible solutions to no avail - When I inspect the network request (and preserve log) I receive the following read out:

• cmd: _cart
  upload: 1
  business: *removed so I could make this post*
  notify_url: https://hategrenade.com/commerce_paypal/ipn/paypal_wps%7Ccommerce_payment_paypal_wps
  bn: CommerceGuys_Cart_PPS
  charset: utf-8
  no_note: 1
  no_shipping: 1
  cancel_return: https://hategrenade.com/checkout/16/payment/back/0V8qngMClSiqkNnuU5k8m1mTLLa7YJDgt3cPuGo0Kog
  return: https://hategrenade.com/checkout/16/payment/return/0V8qngMClSiqkNnuU5k8m1mTLLa7YJDgt3cPuGo0Kog
  rm: 2
  paymentaction: sale
  currency_code: USD
  lc: US
  invoice: 16-1516044175
  amount_1: 27.00
  item_name_1: Order 16 at Hate Grenade
  on0_1: Product count
  os0_1: 1
  form_build_id: form-IcOTdB6r183MAu-xscK9KNlqJ3jjbG_kQYAJlG5Y5tI
  form_id: commerce_checkout_form_payment

All the fields look to be in order and none of the tips from here did the trick...The only other thing I can think of that's different on my end is that I added LetsEncrypt SSL certs.  Could this be a possible cause?  Any advice or instruction would be greatly appreciated.

Best,

Chuck