Recaptcha Problem "ERROR: Invalid domain for site key"

Tue, 16 Jun 2015 09:44:56 +0000
Message: Unexpected status ''
File: /usr/www/users/dogfoe/wortlab/wcf/lib/util/HTTPRequest.class.php (416)
PHP version: 5.5.25
WCF version: 2.1.4 (Typhoon)
Request URI: /index.php/Login/
Referrer: http://www.dogforum.de/index.php/Login/
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Firefox/38.0
Information: ""
Stacktrace: 
  #0 /usr/www/users/dogfoe/wortlab/wcf/lib/util/HTTPRequest.class.php(332): wcf\util\HTTPRequest->parseReplyHeaders()
  #1 /usr/www/users/dogfoe/wortlab/wcf/lib/system/recaptcha/RecaptchaHandlerV2.class.php(36): wcf\util\HTTPRequest->execute()
  #2 /usr/www/users/dogfoe/wortlab/wcf/lib/system/captcha/RecaptchaHandler.class.php(91): wcf\system\recaptcha\RecaptchaHandlerV2->validate('03AHJ_Vut4fvDsx...')
  #3 /usr/www/users/dogfoe/wortlab/wcf/lib/form/AbstractCaptchaForm.class.php(102): wcf\system\captcha\RecaptchaHandler->validate()
  #4 /usr/www/users/dogfoe/wortlab/wcf/lib/form/AbstractCaptchaForm.class.php(94): wcf\form\AbstractCaptchaForm->validateCaptcha()
  #5 /usr/www/users/dogfoe/wortlab/wcf/lib/acp/form/LoginForm.class.php(181): wcf\form\AbstractCaptchaForm->validate()
  #6 /usr/www/users/dogfoe/wortlab/wcf/lib/form/AbstractForm.class.php(61): wcf\acp\form\LoginForm->validate()
  #7 /usr/www/users/dogfoe/wortlab/wcf/lib/acp/form/LoginForm.class.php(153): wcf\form\AbstractForm->submit()
  #8 /usr/www/users/dogfoe/wortlab/wcf/lib/form/AbstractForm.class.php(114): wcf\acp\form\LoginForm->submit()
  #9 /usr/www/users/dogfoe/wortlab/wcf/lib/form/AbstractCaptchaForm.class.php(63): wcf\form\AbstractForm->readData()
  #10 /usr/www/users/dogfoe/wortlab/wcf/lib/acp/form/LoginForm.class.php(229): wcf\form\AbstractCaptchaForm->readData()
  #11 /usr/www/users/dogfoe/wortlab/wcf/lib/page/AbstractPage.class.php(273): wcf\acp\form\LoginForm->readData()
  #12 /usr/www/users/dogfoe/wortlab/wcf/lib/page/AbstractPage.class.php(100): wcf\page\AbstractPage->show()
  #13 /usr/www/users/dogfoe/wortlab/wcf/lib/acp/form/LoginForm.class.php(73): wcf\page\AbstractPage->__run()
  #14 /usr/www/users/dogfoe/wortlab/wcf/lib/system/request/Request.class.php(58): wcf\acp\form\LoginForm->__run()
  #15 /usr/www/users/dogfoe/wortlab/wcf/lib/system/request/RequestHandler.class.php(139): wcf\system\request\Request->execute()
  #16 /usr/www/users/dogfoe/wortlab/index.php(10): wcf\system\request\RequestHandler->handle('wbb')
  #17 {main}