Thank you. Now i got a solution . I changes file permission using SSH. Now it's working fine.
But i had a big problem, just now i fond that
I connected FTP in my host name : 126.96.36.199
In my /app/etc/evc.php file it some thing shows like: 'host' => '/opt/bitnami/mysql/tmp/mysql.sock'......
'http_cache_hosts' => [
'host' => '127.0.0.1',
'port' => '80'
If i changed my Database name still my server "188.8.131.52" working.
After i checked with wrong database name, I had a doubt , Is my FTP connected correctly?
Please let me know.