Fatal error: Uncaught TypeError: Twilio\Base\BaseClient::getAccountSid(): Return value must be of type string, null returned in /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/src/Twilio/Base/BaseClient.php:365 Stack trace: #0 /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/src/Twilio/Rest/Api/V2010.php(128): Twilio\Base\BaseClient->getAccountSid() #1 /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/src/Twilio/Rest/Api/V2010.php(276): Twilio\Rest\Api\V2010->getAccount() #2 /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/src/Twilio/Rest/Client.php(607): Twilio\Rest\Api\V2010->__get('account') #3 /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/src/Twilio/Base/BaseClient.php(298): Twilio\Rest\Client->contextAvailablePhoneNumbers('XX') #4 /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/example/incomingPhoneNumber.php(16): Twilio\Base\BaseClient->__call('availablePhoneN...', Array) #5 /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/example/incomingPhoneNumber.php(28): buyNumber() #6 {main} thrown in /opt/lampp/htdocs/myhospitalnow/propreshnow_nurses/notification_nurses/vendor/twilio/sdk/src/Twilio/Base/BaseClient.php on line 365