XF 2.3 Account Upgrades Not working

[grabacontroller]

Stack trace
#0 src/XF.php(257): XF\Error->logError('Problem getting...', false)

#1 src/XF/Payment/PayPalRest.php(351): XF::logError('Problem getting...')

#2 src/XF/Payment/PayPalRest.php(388): XF\Payment\PayPalRest->getProductById(Object(XF\Purchasable\Purchase), 'user_upgrade_1')

#3 src/XF/Pub/Controller/PurchaseController.php(35): XF\Payment\PayPalRest->initiatePayment(Object(XF\Pub\Controller\PurchaseController), Object(XF\Entity\PurchaseRequest), Object(XF\Purchasable\Purchase))

#4 src/XF/Mvc/Dispatcher.php(362): XF\Pub\Controller\PurchaseController->actionIndex(Object(XF\Mvc\ParameterBag))

#5 src/XF/Mvc/Dispatcher.php(264): XF\Mvc\Dispatcher->dispatchClass('XF:Purchase', 'Index', Object(XF\Mvc\RouteMatch), Object(XF\Pub\Controller\PurchaseController), NULL)

#6 src/XF/Mvc/Dispatcher.php(121): XF\Mvc\Dispatcher->dispatchFromMatch(Object(XF\Mvc\RouteMatch), Object(XF\Pub\Controller\PurchaseController), NULL)

#7 src/XF/Mvc/Dispatcher.php(63): XF\Mvc\Dispatcher->dispatchLoop(Object(XF\Mvc\RouteMatch))

#8 src/XF/App.php(2777): XF\Mvc\Dispatcher->run()

#9 src/XF.php(798): XF\App->run()

#10 index.php(23): XF::runApp('XF\\Pub\\App')

#11 {main}

Request state
array(4) {

  ["url"] => string(41) "/purchase/user_upgrade/?user_upgrade_id=1"

  ["referrer"] => string(44) "https://yourdomain.com/account/upgrades"

  ["_GET"] => array(1) {

    ["user_upgrade_id"] => string(1) "1"

  }

  ["_POST"] => array(6) {

    ["_xfToken"] => string(8) "********"

    ["payment_profile_id"] => string(1) "2"

    ["ct_checkjs"] => string(4) "2024"

    ["_xfRequestUri"] => string(17) "/account/upgrades"

    ["_xfWithData"] => string(1) "1"

    ["_xfResponseType"] => string(4) "json"

  }

}

Whenever I click on purchase, it says:
Oops! We ran into some problems.
Something went wrong. Please try again or contact the administrator.

Also, I am using the default theme.

 

[Old Nick]

["referrer"] => string(44) "https://yourdomain.com/account/upgrades"

Did you modify this line in the error message to hide your domain name?
If not, edit your PayPal configuration with your real domain name...

 

[grabacontroller]

Ya. I modified it to hide my domain name.

 

[grabacontroller]

Bug report already made: https://xenforo.com/community/threads/problem-getting-paypal-product.222950/