Question
Converting psd to png and keeping transparent bg
I have several pds files with transparent backgrounds. I exported them to png-24. When I upload them to have them printed the look black.

This is what it looks like after uploading to a greeting card maker:

- Adobe product and version number: Photoshop CC v 19.1.5
- Operating system and version number

I have searched and done everything I can find on line: the psd is exported as a png-24 
Under Preferences: 
I've also tried 16bit..nothing.
Please HELP!
