If you have uploaded your logo into your Juvo account, yet it is showing a black background when displayed on templates, don't worry it is a quick fix.
This can be caused if you have uploaded your logo as a png file.
You can re-upload your logo using a jpg (image with a transparent background) and this should solve the issue you are having.
Re-upload your logo by using this help article https://juvo.zendesk.com/hc/en-us/articles/360035740952-Add-logo-in-System-Settings