Smartthings Classic App Won't Add Devices

Hello, I had to migrate to v3 hub for my v2 hub was broken. I excluded devices with the Classic app and added the ones which are in the Samsung Connect database with the Samsung Connect app. For the devices with custom DHs such as Monoprice Sensors or GoControl Dimmer switches I read that I have to use the classic app.
The problem is when I try to “Add a Thing” I get the attached screen and the app does not do anything. The manual option are only the non-custom devices.
Please help, thanks.