Can’t authorize plugin

I’m having the exact same issue, running version 4.1.1 of the plugin on WordPress 4.7. I don’t see anything in the HTTP logs of my server, it’s just a silent failure.

I have found “cURL error 60: SSL certificate problem: unable to get local issuer certificate (see https://curl.haxx.se/libcurl/c/libcurl-errors.html)” in the ctct_token_response parameter in the wp_options table. Is this error from my host or katz.co? I’ve attempted to add my cabundle to the curl.cainfo parameter with no luck.

I dug into the plugin code a bit and found that nothing else is logged but this error in the database. I added some echo statements and this was the output:

cURL error 60: SSL certificate problem: unable to get local issuer certificate (see https://curl.haxx.se/libcurl/c/libcurl-errors.html)#0 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Handler\CurlFactory.php(150): GuzzleHttp\Handler\CurlFactory::createRejection(Object(GuzzleHttp\Handler\EasyHandle), Array) #1 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Handler\CurlFactory.php(103): GuzzleHttp\Handler\CurlFactory::finishError(Object(GuzzleHttp\Handler\CurlHandler), Object(GuzzleHttp\Handler\EasyHandle), Object(GuzzleHttp\Handler\CurlFactory)) #2 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Handler\CurlHandler.php(43): GuzzleHttp\Handler\CurlFactory::finish(Object(GuzzleHttp\Handler\CurlHandler), Object(GuzzleHttp\Handler\EasyHandle), Object(GuzzleHttp\Handler\CurlFactory)) #3 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Handler\Proxy.php(28): GuzzleHttp\Handler\CurlHandler->__invoke(Object(GuzzleHttp\Psr7\Request), Array) #4 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Handler\Proxy.php(51): GuzzleHttp\Handler\Proxy::GuzzleHttp\Handler\{closure}(Object(GuzzleHttp\Psr7\Request), Array) #5 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\PrepareBodyMiddleware.php(42): GuzzleHttp\Handler\Proxy::GuzzleHttp\Handler\{closure}(Object(GuzzleHttp\Psr7\Request), Array) #6 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Middleware.php(30): GuzzleHttp\PrepareBodyMiddleware->__invoke(Object(GuzzleHttp\Psr7\Request), Array) #7 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\RedirectMiddleware.php(68): GuzzleHttp\Middleware::GuzzleHttp\{closure}(Object(GuzzleHttp\Psr7\Request), Array) #8 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Middleware.php(59): GuzzleHttp\RedirectMiddleware->__invoke(Object(GuzzleHttp\Psr7\Request), Array) #9 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\HandlerStack.php(67): GuzzleHttp\Middleware::GuzzleHttp\{closure}(Object(GuzzleHttp\Psr7\Request), Array) #10 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Client.php(268): GuzzleHttp\HandlerStack->__invoke(Object(GuzzleHttp\Psr7\Request), Array) #11 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Client.php(123): GuzzleHttp\Client->transfer(Object(GuzzleHttp\Psr7\Request), Array) #12 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\guzzlehttp\guzzle\src\Client.php(129): GuzzleHttp\Client->requestAsync('POST', 'https://oauth2....', Array) #13 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\vendor\constantcontact\constantcontact\src\Ctct\Auth\CtctOAuth2.php(73): GuzzleHttp\Client->request('POST', 'https://oauth2....', Array) #14 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\classes\class.kwsoauth2.php(82): Ctct\Auth\CtctOAuth2->getAccessToken('hIfPRwycoVFa1x5...') #15 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\classes\class.kwsoauth2.php(43): KWSOAuth2::processResponse() #16 C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\constant-contact-api.php(122): KWSOAuth2->__construct() #17 [internal function]: WP_CTCT->setup('') #18 C:\inetpub\wwwroot\wp-includes\class-wp-hook.php(298): call_user_func_array(Array, Array) #19 C:\inetpub\wwwroot\wp-includes\class-wp-hook.php(323): WP_Hook->apply_filters('', Array) #20 C:\inetpub\wwwroot\wp-includes\plugin.php(453): WP_Hook->do_action(Array) #21 C:\inetpub\wwwroot\wp-settings.php(326): do_action('plugins_loaded') #22 C:\inetpub\wwwroot\wp-config.php(96): require_once('C:\\inetpub\\wwwr...') #23 C:\inetpub\wwwroot\wp-load.php(37): require_once('C:\\inetpub\\wwwr...') #24 C:\inetpub\wwwroot\wp-blog-header.php(13): require_once('C:\\inetpub\\wwwr...') #25 C:\inetpub\wwwroot\index.php(17): require('C:\\inetpub\\wwwr...') #26 {main}
Warning: Cannot modify header information - headers already sent by (output started at C:\inetpub\wwwroot\wp-content\plugins\constant-contact-api\classes\class.kwsoauth2.php:100) in C:\inetpub\wwwroot\wp-includes\pluggable.php on line 1179

What do I need to configure on your environment to allow this authorization to work?