My mom is upset after tapping to catch a Pokemon game stops responding desperate for a fix!

My mom loves playing Pokemon go she is level 34 and has never had a problem like this before! it just started 2 days ago and we have been unable to fix it since. With gen 2 coming out my mom is very worried she wont ever be able to play again! She has an android Samsung galaxy s7. She can hit Pokestops and gyms no problem but when she taps on a wild Pokemon the phone starts to lag. in about 3-4 frames the game slowly zooms towards the Pokemon but then it crashes and says it has "unfortunately, Pokemon go has stopped". We haven't seen this problem before don't know what or why its happening now. Already cleared the cache of the game and phone. reinstalled the app multiple times. I really don't know what the problem is. If anyone has had this problem before or can point me in the right direction i would greatly appreciate it. Thanks!