Warning: Undefined array key "userPhone" in /home/apphfbdc/public_html/pwitter/send.verification.code.php on line 19

Fatal error: Uncaught TypeError: Twilio\Rest\Api\V2010\Account\MessageList::create(): Argument #1 ($to) must be of type string, null given, called in /home/apphfbdc/public_html/pwitter/send.verification.code.php on line 33 and defined in /home/apphfbdc/public_html/pwitter/vendor/twilio/sdk/src/Twilio/Rest/Api/V2010/Account/MessageList.php:44 Stack trace: #0 /home/apphfbdc/public_html/pwitter/send.verification.code.php(33): Twilio\Rest\Api\V2010\Account\MessageList->create() #1 {main} thrown in /home/apphfbdc/public_html/pwitter/vendor/twilio/sdk/src/Twilio/Rest/Api/V2010/Account/MessageList.php on line 44