WP 博客总出现500错误，咋回事？

wordpress 博客总是出现500错误，咋回事？

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, [email protected] and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

按照这篇文章 http://2018live.com/archives/69
.htaccess文件 和文件权限 都没问题。
昨天换到一台VPS上，今天上午手机访问还是出现 500错误。没办法，又迁移回来了！
另外 我用的是DH主机，同用户名下 其他wordpress blog 都正常。

请哪位达人指点下！