really I've this site build with Joomla located on hostmonster

but all Joomla website require a database support to operate this database is on AWS configuration files have to be up-to-date for your I must change host address I place the IP (of AWS host) in host however it displayed "not able for connecting to database MySQL" can u assist me ?????????

Consider your security configurations for the server on AWS. Probably you will have to open port 3306 in your firewall. This can be done while using AWS Console.

I'd strongly advise reading through with the security guidelines for MySQL.

suppose you've database on server B and website on server A(say it's IP 192.234.12.1)

on cpanel whitelist the IP of server B

and make up a new user getting sufficient rights in database (say this user is test)

then create this user as test@192.234.12.1