I have the same/similar problem.
iPad Air iOS 8 with Sonic Port XV
mobile pod v.1.06.1f
Privacy ... microphone access allowed to mobile pod application
But still I get the pop up "Line 6 Device Not Found"
Clicking on the Line6 logo at the bottom the second line says Device: Device Not Connected.
Further Information:
After several tries to connect/disconnect, start/stop the application, turn privacy off/on I gave up and tried on iPhone 5s iOS8 same version of mobile pod.
There it was working immediately - though not stable, the app crashed twice after few minutes use.
The device was also successfully recognized by other apps (immediately with AmpKit, with some flaws by Amplitube) I was using before ...
I tried these apps then again on the iPad air, they were not working there like mobile pod before :-(
... so I would assume, that this is not an mobile pod issue, but a sonicport<->ipad issue,
... is there a firmware upgrade for sonic port XV available by any chance?!
Thanks for your support!