I have developed a new website using the latest version of Joomla 3.X.
It is in a sub-directory under my own web site while being developed.
In my excitement to move it to the new host site and launch...I forgot to back it up.

I downloaded the Joomla files, and downloaded the database and migrated to the new hosting site, changed the paths' in the config.php etc. I've done this once before with success, but doesn't mean I didn't do something wrong.
when I loaded the site all I got was a white page with one word: Error.
I thought it was from the migration but I have since discovered the original development site has the same issue.
All the files seem to be in place, as is the database. The config file appears to be the same. But still a white page with one word: 'Error'.
I must have done something without realising it. Is this a database connection error? I just can't find what is wrong.
Very much appreciate your help, especially if you treat me like a kindergarten developer with minimal jargon understanding.
Leonie