Internet connection with the Photoshop plugin
To use remove.bg for Photoshop, you need to allow Photoshop extension to connect to the internet. Otherwise, you will get this error:
To fix the problem you just need to open Photoshop and go to Edit → Preferences → Plug-ins... and verify that there is a checkmark next to Allow Extensions to Connect to the Internet.
If you change the setting, restart Photoshop to make sure the change is applied.