Now the site doesn't show and we get the following Error on the home page
Exception: Notice: Use of undefined constant ICONV_IMPL - assumed 'ICONV_IMPL' in /home/tassosco/public_html/vendor/magento/framework/Stdlib/StringUtils.php on line 162 in /home/tassosco/public_html/vendor/magento/framework/App/ErrorHandler.php:61 Stack trace: #0 /home/tassosco/public_html/vendor/magento/framework/Stdlib/StringUtils.php(162): Magento\Framework\App\ErrorHandler->handler(8, 'Use of undefine...', '/home/tassosco/...', 162, Array) #1 /home/tassosco/public_html/vendor/magento/framework/HTTP/Header.php(120): Magento\Framework\Stdlib\StringUtils->cleanString('Mozilla/5.0 (X1...') #2 /home/tassosco/public_html/vendor/magento/framework/HTTP/Header.php(57): Magento\Framework\HTTP\Header->_getHttpCleanValue('HTTP_USER_AGENT', true) #3 /home/tassosco/public_html/vendor/magento/framework/App/Response/HeaderProvider/XssProtection.php(43): Magento\Framework\HTTP\Header->getHttpUserAgent() #4 /home/tassosco/public_html/vendor/magento/framework/App/Response/HeaderManager.php(42): Magento\Framework\App\Response\HeaderProvider\XssProtection->getValue()
5 /home/tassosco/public_html/vendor/magento/framework/Interception/Interceptor.php(123):
Magento\Framework\App\Response\HeaderManager->beforeSendResponse(Object(Magento\Framework\App\Response\Http\Interceptor))
6 /home/tassosco/public_html/var/generation/Magento/Framework/App/Response/Http/Interceptor.php(117):
Magento\Framework\App\Response\Http\Interceptor->___callPlugins('sendResponse', Array, Array) #7 /home/tassosco/public_html/vendor/magento/framework/App/Http.php(185): Magento\Framework\App\Response\Http\Interceptor->sendResponse() #8 /home/tassosco/public_html/vendor/magento/framework/App/Http.php(156): Magento\Framework\App\Http->handleDeveloperMode(Object(Magento\Framework\App\Bootstrap), Object(Exception)) #9 /home/tassosco/public_html/vendor/magento/framework/App/Bootstrap.php(263): Magento\Framework\App\Http->catchException(Object(Magento\Framework\App\Bootstrap), Object(Exception)) #10 /home/tassosco/public_html/index.php(39): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http))
11 {main}
please help me?