Magento – Getting error of “An error occurred while processing your form. Please try again later.” after submitting a form

I am Getting error of

An error occurred while processing your form. Please try again later.

after submitting a form.

Here is my code
app/code/Smartwave/Porto/Model/Post.php

    <?php
/**
 *
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Contact\Controller\Index;

use Magento\Contact\Model\ConfigInterface;
use Magento\Contact\Model\MailInterface;
use Magento\Framework\App\Action\Context;
use Magento\Framework\App\Request\DataPersistorInterface;
use Magento\Framework\Controller\Result\Redirect;
use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\HTTP\PhpEnvironment\Request;
use Psr\Log\LoggerInterface;
use Magento\Framework\App\ObjectManager;
use Magento\Framework\DataObject;

class Post extends \Magento\Contact\Controller\Index
{
    /**
     * @var DataPersistorInterface
     */
    private $dataPersistor;

    /**
     * @var Context
     */
    private $context;

    /**
     * @var MailInterface
     */
    private $mail;

    /**
     * @var LoggerInterface
     */
    private $logger;

    /**
     * @param Context $context
     * @param ConfigInterface $contactsConfig
     * @param MailInterface $mail
     * @param DataPersistorInterface $dataPersistor
     * @param LoggerInterface $logger
     */
    public function __construct(
        Context $context,
        ConfigInterface $contactsConfig,
        MailInterface $mail,
        DataPersistorInterface $dataPersistor,
        LoggerInterface $logger = null
    ) {
        parent::__construct($context, $contactsConfig);
        $this->context = $context;
        $this->mail = $mail;
        $this->dataPersistor = $dataPersistor;
        $this->logger = $logger ?: ObjectManager::getInstance()->get(LoggerInterface::class);
    }

    /**
     * Post user question
     *
     * @return Redirect
     */
    public function execute()
    {
        if (!$this->isPostRequest()) {
            return $this->resultRedirectFactory->create()->setPath('*/*/');
        }
        try {
            $this->sendEmail($this->validatedParams());
            $this->messageManager->addSuccessMessage(
                __('Thanks for contacting us with your comments and questions. We\'ll respond to you very soon.')
            );
            $this->dataPersistor->clear('contact_us');
        } catch (LocalizedException $e) {
            $this->messageManager->addErrorMessage($e->getMessage());
            $this->dataPersistor->set('contact_us', $this->getRequest()->getParams());
        } catch (\Exception $e) {
            $this->logger->critical($e);
            $this->messageManager->addErrorMessage(
                __('An error occurred while processing your form. Please try again later.')
            );
            $this->dataPersistor->set('contact_us', $this->getRequest()->getParams());
        }
        return $this->resultRedirectFactory->create()->setPath('contact/index');
    }

    /**
     * @param array $post Post data from contact form
     * @return void
     */
    private function sendEmail($post)
    {
        $this->mail->send(
            $post['email'],
            ['data' => new DataObject($post)]
        );
    }

    /**
     * @return bool
     */
    private function isPostRequest()
    {
        /** @var Request $request */
        $request = $this->getRequest();
        return !empty($request->getPostValue());
    }

    /**
     * @return array
     * @throws \Exception
     */
    private function validatedParams()
    {
        $request = $this->getRequest();
        if (trim($request->getParam('name')) === '') {
            throw new LocalizedException(__('Name is missing'));
        }
        if (trim($request->getParam('comment')) === '') {
            throw new LocalizedException(__('Comment is missing'));
        }
        if (false === \strpos($request->getParam('email'), '@')) {
            throw new LocalizedException(__('Invalid email address'));
        }
        if (trim($request->getParam('hideit')) !== '') {
            throw new \Exception();
        }

        return $request->getParams();
    }
}

app/design/frontend/Smartwave/porto/Magento_Contact/templates/form.phtml

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

// @codingStandardsIgnoreFile
/** @var \Magento\Contact\Block\ContactForm $block */
?>
<form class="form contact"
      action="<?= $block->escapeUrl($block->getFormAction()) ?>"
      id="contact-form"
      method="post"
      data-hasrequired="<?= $block->escapeHtmlAttr(__('* Required Fields')) ?>"
      data-mage-init='{"validation":{}}'>
    <fieldset class="fieldset">
        <legend class="legend"><span><?= $block->escapeHtml(__('Write Us')) ?></span></legend><br />
        <div class="field note no-label"><?= $block->escapeHtml(__('Jot us a note and we’ll get back to you as quickly as possible.')) ?></div>
        <div class="field name required">
            <label class="label" for="name"><span><?= $block->escapeHtml(__('Name')) ?></span></label>
            <div class="control">
                <input name="name" id="name" title="<?= $block->escapeHtmlAttr(__('Name')) ?>" value="<?= $block->escapeHtmlAttr($this->helper('Magento\Contact\Helper\Data')->getPostValue('name') ?: $this->helper('Magento\Contact\Helper\Data')->getUserName()) ?>" class="input-text" type="text" data-validate="{required:true}"/>
            </div>
        </div>
        <div class="field email required">
            <label class="label" for="email"><span><?= $block->escapeHtml(__('Email')) ?></span></label>
            <div class="control">
                <input name="email" id="email" title="<?= $block->escapeHtmlAttr(__('Email')) ?>" value="<?= $block->escapeHtmlAttr($this->helper('Magento\Contact\Helper\Data')->getPostValue('email') ?: $this->helper('Magento\Contact\Helper\Data')->getUserEmail()) ?>" class="input-text" type="email" data-validate="{required:true, 'validate-email':true}"/>
            </div>
        </div>
        <div class="field telephone">
            <label class="label" for="telephone"><span><?= $block->escapeHtml(__('Phone Number')) ?></span></label>
            <div class="control">
                <input name="telephone" id="telephone" title="<?= $block->escapeHtmlAttr(__('Phone Number')) ?>" value="<?= $block->escapeHtmlAttr($this->helper('Magento\Contact\Helper\Data')->getPostValue('telephone')) ?>" class="input-text" type="text" />
            </div>
        </div>
        <div class="field comment required">
            <label class="label" for="comment"><span><?= $block->escapeHtml(__('What’s on your mind?')) ?></span></label>
            <div class="control">
                <textarea name="comment" id="comment" title="<?= $block->escapeHtmlAttr(__('What’s on your mind?')) ?>" class="input-text" cols="5" rows="3" data-validate="{required:true}"><?= $block->escapeHtml($this->helper('Magento\Contact\Helper\Data')->getPostValue('comment')) ?></textarea>
            </div>
        </div>
        <?= $block->getChildHtml('form.additional.info') ?>
    </fieldset>
    <div class="actions-toolbar">
        <div class="primary">
            <input type="hidden" name="hideit" id="hideit" value="" />
            <button type="submit" title="<?= $block->escapeHtmlAttr(__('Submit')) ?>" class="action submit primary">
                <span><?= $block->escapeHtml(__('Submit')) ?></span>
            </button>
        </div>
    </div>
</form>

app/design/frontend/Smartwave/porto/Magento_Contact/layout/contact_index_index.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © 2015 Magento. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" layout="1column" xsi:noNamespaceSchemaLocation="../../../../../../../lib/internal/Magento/Framework/View/Layout/etc/page_configuration.xsd">
    <head>
        <title>Contact Us</title>
    </head>
    <body>
        <referenceContainer name="page.top">
            <block class="Smartwave\Porto\Block\Template" name="google_map" template="Magento_Contact::google_map.phtml"/>
        </referenceContainer>
        <referenceContainer name="content">
            <block class="Smartwave\Porto\Block\Template" name="contactPage" template="Magento_Contact::contact_page.phtml">
                <block class="Magento\Contact\Block\ContactForm" name="contactForm" template="Magento_Contact::form.phtml">
                    <container name="form.additional.info" label="Form Additional Info"/>
                </block>
            </block>
        </referenceContainer>
    </body>
</page>