Delete action return failed message

Error message
```
Deletion failed: There has been a critical error on your website.Learn more about debugging in WordPress.
```

Ref: https://youtu.be/_dUVPpMEnYc

Error logs
```
2020/05/23 17:46:10 [error] 103#103: *40 FastCGI sent in stderr: "PHP message: PHP Warning: require_once(/usr/html/wp-content/plugins/simplerstatic/includes/class-ss-plugin.php): failed to open stream: No such file or directory in /usr/html/wp-content/plugins/simplerstatic/uninstall.php on line 14PHP message: PHP Fatal error: require_once(): Failed opening required '/usr/html/wp-content/plugins/simplerstatic/includes/class-ss-plugin.php' (include_path='.:/usr/share/php7') in /usr/html/wp-content/plugins/simplerstatic/uninstall.php on line 14" while reading response header from upstream, client: 172.17.0.1, server: , request: "POST /wp-admin/admin-ajax.php HTTP/1.1", upstream: "fastcgi://unix:/var/run/php7-fpm.sock:", host: "ftp.localhost:4046", referrer: "http://ftp.localhost:4046/wp-admin/plugins.php"
```