quickbook-sync-payments

"""
Client error: `POST https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer` resulted in a `401 Unauthorized` response:\n
{"error":"invalid_client"}\n
"""

Notice: Undefined variable: response in /home/souq/public_html/wp-content/plugins/quickbook360/QB/Classes/Intuit.php on line 178

Fatal error: Uncaught Error: Call to a member function getBody() on null in /home/souq/public_html/wp-content/plugins/quickbook360/QB/Classes/Intuit.php:178 Stack trace: #0 /home/souq/public_html/wp-content/plugins/quickbook360/QB/Classes/Intuit.php(140): QB\Classes\Intuit->makePostRequest('payment', Array) #1 /home/souq/public_html/wp-content/plugins/quickbook360/QB/Classes/Payment.php(29): QB\Classes\Intuit->createPayment(Array) #2 /home/souq/public_html/wp-content/plugins/quickbook360/QB/Classes/QuickBooks.php(108): QB\Classes\Payment->createPayment() #3 /home/souq/public_html/wp-includes/shortcodes.php(319): QB\Classes\QuickBooks->autoPay('', '', 'quickbook-sync-...') #4 [internal function]: do_shortcode_tag(Array) #5 /home/souq/public_html/wp-includes/shortcodes.php(197): preg_replace_callback('/\\[(\\[?)(quickb...', 'do_shortcode_ta...', '[quickbook-sync...') #6 /home/souq/public_html/wp-includes/class-wp-hook.php(286): do_shortcode('[quickbook-sync...') #7 /home/souq/public_html/wp-includes/plugin.php(203): WP_Hook in /home/souq/public_html/wp-content/plugins/quickbook360/QB/Classes/Intuit.php on line 178