Please see this FAQ regarding the 'Config file not found.' message:
When I view my gallery I see the message 'Config file not found'. How do I fix this?
If you encounter this message, then the gallery's configuration file is likely to be in the wrong location.
By default, the gallery's configuration file should be named 'config.xml' and should be located in the same directory as the web page containing the gallery's embedding code.
If you rename or relocate the gallery's configuration file, then you can point towards it with a configUrl entry in your gallery's embedding code.
The configUrl entry can be an absolute path (in the form http://www.example.com/gallery/custom.xml) or a relative path (relative to the web page containing the gallery's embedding code).
Also, if you use a baseUrl entry in your gallery's embedding code (to point towards a gallery folder), then a relative configUrl will be relative to the baseUrl.
Short descriptions of all the Embed Options (such as configUrl and baseUrl) can be found here.
Another possible reason for encountering the 'Config file not found.' message would be if the configuration file is somehow corrupt or incomplete.
Open your gallery's 'config.xml' file directly in a browser and the browser should let you know if there are any syntax errors in the code (which you can then correct).
If you encounter the exact text 'Config XML file not found.', then you are using an older version of Juicebox.
In v1.5.0 (released on 24 May 2016), Juicebox first supported JSON configuration files as well as XML configuration files and the error message was changed from 'Config XML file not found.' to 'Config file not found.'.
I'd recommend that you upgrade your Juicebox gallery to the latest version (v1.5.1) to ensure that any bugs from previous versions (which have since been fixed) are not contributing to your problem.
For reference, full instructions for Upgrading Juicebox can be found here.
I hope my notes above help.
However, if you continue to experience difficulties, then please post the URL to your gallery's web page so that I can see the problem for myself and hopefully help further.
Thank you.