오전까지 뜨던게 갑자기 사이트가 안뜨는데 메일 들어가보니까 이런 메일이 왔거든요.
봐도 모르겠어서요. 

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Since WordPress 5.2 there is a built-in feature that detects when a plugin or theme causes a 
fatal error on your site, and notifies you with this automated email.

이 경우 WordPress에서 테마 Heap에 오류가 발생합니다.

First, visit your website (http://mely1004.byus.net/wordpress/) and check for any visible 
issues. Next, visit the page where the error was caught 
(http://mely1004.byus.net/wordpress/wordpress/wp-admin/admin-ajax.php) and check for any 
visible issues.

이 문제를 더 조사하는 데 도움이 필요하면 호스트에 문의하십시오.

If your site appears broken and you can't access your dashboard normally, WordPress now has a 
special "recovery mode". This lets you safely login to your dashboard and investigate further.

http://mely1004.byus.net/wordpress/wp-login.php?
action=enter_recovery_mode&rm_token=rFhEGkpd7vtv8RxBnzeizY&rm_key=KAI4b4dX8Eykw2DUTQiWJV

To keep your site safe, this link will expire in 1 일. Don't worry about that, though: a new 
link will be emailed to you if the error occurs again after it expires.

When seeking help with this issue, you may be asked for some of the following information:
워드프레스 버전 5.3.2
Current theme: Heap (version 1.5.9)
Current plugin:  (version )
PHP version 5.6.40



오류 세부 정보
====================
/home1/mely1004/public_html/wordpress/wp-content/themes/heap/wpgrade-
core/classes/WPGradeOptions.php 파일의 90 줄에서 오류타입 E_ERROR 가 발생했습니다. 오류메시지: 
Call to undefined method WPGradeOptionDriver_Config::get_args()