Email Functionality not Working in 2.3.0

Finally I have Found Solution and Now it's Working

$sender = [    
           'email' => $this->_escaper->escapeHtml($customer_email),
           'name' => $this->_escaper->escapeHtml($customer_name)
         ];

$to_email = $this->_helper->getSendMailTo();

$transport= $this->_transportBuilder->setTemplateIdentifier('config_email_settings_email_template')
        ->setTemplateOptions($templateOptions)
        ->setTemplateVars($templateVars)
        ->setFrom($sender)
        ->addTo($to_email, 'Name')
        ->getTransport();

$transport->sendMessage();

Please replace your code with following code and check after clear your cache, also please remove "_escaper" from your code.

$transport = $this->transportBuilder
            ->setTemplateIdentifier('config_email_settings_email_template')
            ->setTemplateOptions(
                [
                    'area' => \Magento\Framework\App\Area::AREA_FRONTEND,
                    'store' => $this->storeManager->getStore()->getId()
                ]
            )
            ->setTemplateVars($variables)
            ->setFrom($emailSender)
            ->addTo($emailRecipient)
            ->setReplyTo($replyToEmail, $replyToName)
            ->getTransport();

        $transport->sendMessage();

Since Magento 2.3, Magento uses Zend Framework 2 for sending emails. Which probably changed the logic used for parsing array with the recipient data.

---

So here are few variants on how you can properly send email in Magento 2.3:

1. For multiple recipients: use array where key is the recipient's email address and value - recipient's name (note, the same rules applied to sender details):

$sender = [$this->_escaper->escapeHtml($customer_email) => $this->_escaper->escapeHtml($customer_name)];

$to_email = $this->_helper->getSendMailTo();

$sendToInfo = [$this->_escaper->escapeHtml($to_email) => 'Recipient Name'];

$transport = $this->_transportBuilder->setTemplateIdentifier('config_email_settings_email_template')
                    ->setTemplateOptions($templateOptions)
                    ->setTemplateVars($templateVars)
                    ->setFrom($sender)
                    ->addTo($sendToInfo)
                    ->getTransport();


$transport->sendMessage();

2. Or you can use the code below to send an email to a single recipient. This code is backward compatible with Magento 2.2 and lower versions:

$to_email = $this->_helper->getSendMailTo();

$transport = $this->_transportBuilder->setTemplateIdentifier('config_email_settings_email_template')
                    ->setTemplateOptions($templateOptions)
                    ->setTemplateVars($templateVars)
                    ->setFrom($this->_escaper->escapeHtml($customer_email))
                    ->addTo($this->_escaper->escapeHtml($to_email))
                    ->getTransport();


$transport->sendMessage();