Yesterday my DJI Go app started saying  "Current DJIDevice: phantom3 professional, Use the DJI GoApp for this device. This happens on two different tablets and two different phones,Amy help would be appreciated, cannot connect with any device.

Hi. Can we safely assume that you're using the DJI GO 4 app, and not the original DJI GO app?

That seems odd, did you notice this after an app or firmware update? Which mobile devices have you tried thus far? What Go4 app version are you using?

And to add to Jamie's post, there is a difference in how Android and iOS versions of GO 4 (which you should be using) are installed. For Android, you need to ensure that another app hasn't commandeered the USB port as default.