vvfly8

I have verified the wp-config.php.
When I Changed the item such as ‘define user’ or ‘define password’ in wp-config.php,then filled in the setupconfig.php site,it showed a error message which means database can not connect.I thought the wp-config was correct.
Then I defined the item that in the wp-config.php which I copied all from wp-config-sample.php,or the content that from the etup config.php website showed.Same.
Think about it,When I completed the installation in vps, I configed the web successed once at the first time.I wrote something and post.Then I reboot the system,it does’t works.
If you suspect it’s a permission issue,what about it?
1.the wp-config permission? it’s nginx:nginx can wirte
2.DB, user and password same as wp-config
anthing else?
Thanks.