Magento 2 – Fix ‘Invalid Sender Data’ Error When Sending Custom Email

Below is code that i am using send mail , and getting 'Invalid sender data'

<?php
    namespace Mycompany\Orderupdate\Helper;
    use Exception;
    use Psr\Log\LoggerInterface;
    use Magento\Framework\Mail\Template\TransportBuilder;
    use Magento\Framework\Translate\Inline\StateInterface;
    use Magento\Framework\App\Area;
    use Magento\Framework\App\Config\ScopeConfigInterface;
    use Magento\Store\Model\ScopeInterface;


    /**
     * Class Sendmail
     * @package Mycompany\Orderupdate\Model
     */
    class Sendmail
    {
        /**
         * Sender email
         */
        const SENDER_EMAIL='trans_email/ident_general/email';
        /**
         * Email Template
         */
        const EMAIL_TEMPLATE='orderupdate/email/email_template';
        /**
         * @var \Magento\Framework\Mail\Template\TransportBuilder
         */
        protected $transportBuilder;

        /**
         * @var \Magento\Framework\Translate\Inline\StateInterface
         */
        protected $inlineTranslation;

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

        /**
         * @var \Magento\Store\Model\StoreManagerInterface
         */
        protected $_storeManager;
        protected $request;
        protected $scopeConfig;
        /**
         * ChangeRequestEmailSender constructor
         *
         * @param TransportBuilder $transportBuilder
         * @param StateInterface   $inlineTranslation
         * @param \Magento\Store\Model\StoreManagerInterface $storeManager
         */
        public function __construct(
            TransportBuilder $transportBuilder,
            StateInterface $inlineTranslation,
            LoggerInterface $logger,
            ScopeConfigInterface $scopeConfig,
            \Magento\Store\Model\StoreManagerInterface $storeManager
        )
        {
            $this->transportBuilder = $transportBuilder;
            $this->inlineTranslation = $inlineTranslation;
            $this->logger = $logger;
            $this->_storeManager = $storeManager;
            $this->scopeConfig = $scopeConfig;
        }

        public function sendEmailOnDelivery($order, $customerName, $customerEmail)
        {
            $this->inlineTranslation->suspend();
            $orderId=$order->getId();
            $adminAmail = $this->senderEmail();
            $emailtemplate = $this->emailTemplate();
            try {
                $templateVars = [
                    'name' => $customerName,
                    'orderId' => $orderId
                ];
                $transport = $this->transportBuilder
                    ->setTemplateIdentifier($emailtemplate)
                    ->setTemplateOptions
                    (
                        [
                            'area' => Area::AREA_ADMINHTML,
                            'store' => $this->_storeManager->getStore()->getId()
                        ]
                    )
                    ->setTemplateVars($templateVars)
                    ->setFrom($adminAmail)
                    ->addTo($customerEmail,$customerName)
                    ->getTransport();
                $transport->sendMessage();
                $this->inlineTranslation->resume();
            } catch (Exception $e) {
                print_r($e->getMessage());
                exit;
                $this->inlineTranslation->resume();
            }
        }

        public function senderEmail()
        {
            $storeScope = ScopeInterface::SCOPE_STORE;
            return $this->scopeConfig->getValue(
                self::SENDER_EMAIL,
                $storeScope
            );
        }
     public function emailTemplate()
        {
            $storeScope = ScopeInterface::SCOPE_STORE;
            return $this->scopeConfig->getValue(
                self::EMAIL_TEMPLATE,
                $storeScope
            );
        }

    }

Tried to debug where is exception from vendor\magento\module-email\Model\Template\SenderResolver.php

 public function resolve($sender, $scopeId = null)
    {
        $result = [];

        if (!is_array($sender)) {
            $result['name'] = $this->_scopeConfig->getValue(
                'trans_email/ident_' . $sender . '/name',
                \Magento\Store\Model\ScopeInterface::SCOPE_STORE,
                $scopeId
            );
            $result['email'] = $this->_scopeConfig->getValue(
                'trans_email/ident_' . $sender . '/email',
                \Magento\Store\Model\ScopeInterface::SCOPE_STORE,
                $scopeId
            );
        } else {
            $result = $sender;
        }

        if (!isset($result['name']) || !isset($result['email'])) {
            throw new \Magento\Framework\Exception\MailException(__('Invalid sender data'));
        }

        return $result;
    }

I am getting a blank array in $sender , but I'm passing value in $adminAmail.