Is the Device Preview service no longer available?

Personally, I use a local testing server (XAMPP) to preview across any device linked to the network...

https://helpx.adobe.com/dreamweaver/using/set-testing-server.html

Place your site's root folder within XAMPP's htdocs folder, then run XAMPP as Administrator. From there on, any device that shares the network can view your site by going to your machine's internal network IP followed by the site's root folder name, for example: 10.5.160.96/MySite2.

It makes testing across multiple devices much easier, since I can email a link to the entire office for testing on their various mobile devices, laptops and desktops. If an issue appears, they send me a quick screen shot and I tweek code.

This was removed in release back in November of last year ( https://helpx.adobe.com/dreamweaver/using/device-preview.html ).  This is the recommended replacement from Adobe ( https://helpx.adobe.com/dreamweaver/using/previewing-pages.html ).