User blog comment:Dman6233/OT Live Action Teen Titans Series to air on DC Digital Service and be produced by Arrowverse writer, Greg Berlanti in 2018/@comment-4300738-20170427021457

It almost has to be on Earth-1 or Earth-38. (Though I'm leaning towards Earth-1 since a Robin costume cameo'd in Constantine and Bruce Wayne's company exists on that Earth as well.)

I doubt it's in the DCEU.