This question might yield better results if it was moved/posted in the P2V section of the forum.
Also, please consider changing your title to something more specific than "Lichi," which is misspelled anyway. "Can Litchi replace the DJI Vision app for my P2V" might attract the people who know the answer you're looking for.
The way the P2V and P2V+ connect to the DJI Vision app is totally different than how the P3 connects via cable to the phone or tablet and then to the DJI GO app. People familiar with the P3 and later Phantoms may have no knowledge of the Phantom 2 Vision models and how they connected.
DJI's Vision method of creating a wifi for the phone/tablet to connect with was always unreliable for me. My P2V+'s RE700 wifi extender was prone to overheating and its reliability was inconsistent.
I'd bet your problem is with the wifi extender and not with the app. I believe the P2V used an RE500 but the RE700 is compatible, and gives more range.