WordPress Authentication

BACKGROUND: This is a continuation of a prior problem with regard to hosting a test-server and web server application on two different physical sites with the same domain name and log-in information. On the test server I access a blank page, and on the web server I am told that there is an error establish a database connection.

https://wordpress.org/support/topic/getting-help-on-wordpress

QUESTION: Since whatever is installed is automatically set to access the wordpress.org website, is it not likely that I should be using completely different log-in information for each site. For example, I am using the same email address for both sites.

I have already applied my knowledge of phpMyAdmin to insure that the proper prefixes were affixed, but this does not appear to be enough.