Error: "your PHP server doesn’t MySQL module loaded ’t mysql_(p)connect function"

Just tried adding a MySql database in my version of CS4. For the first time I have got the above error message trying to connect, tho the database is successfully configged.
Is this due to DW deprecated connection set-up and would the issues go away if i use your MySQLi extension?
I will be later using it in DW CC 2017 but need to get some quick work done so have tried to use my old, fairly trusted CS4 version for the moment.
Advice gratefully received!
Cheers guys

This message means that your server doesn't have mysql installed. Have you tried creating a page with <?php phpinfo(); ?> and make sure mysql is listed as an installed component? You may need to enable it in the php.ini file.

They say....
" suggest to try to use MySQLi extension since it is recommended to use. It is not recommended to use the old mysql extension, as it was deprecated in PHP 5.5.0 and as per checking here, your web scripting is now on PHP 7.0 so you should have use MySQLi."
So presumably I should buy your extension?!

You can either ask your hosting provider to downgrade your server to a version lower than 7 or you can use our MySQLi Server Behaviors extension to do your database connections and interactions with MySQLi.

DW 2019 + mysqli sb W10 Xamp and Mysql community server 5.7.22

With dynamic connection or mysqli SB I get the error. (mysql server and other mysqli connection work well with other software). Please help

SOLVED
in my case the error was due a configuration error for the local testing server