Android App Debugging

Hello everyone, I have an android App developed in android studio, which I bought from a freelancer, along with a microcontroller system. I take some temperature measurements from a sensor (DHT11) and I send them to the mobile, wirelessly through an NodeMCU ESP's wifi shield hot spot. I try to run the app and this error occurs on an xperia z1 android version: 5.1.1: "Unfortunatelly the GraphPlotterESP has stopped working" This is the source code and the apk of the app: [login to view URL] ( I attach a second version of the apk) I have an arduino connected to a NodeMCU esp with wifi shield and a DHT11 sensor of temperature connected on both, as seen on the screenshot attached. I connect to the wireless network of the NodeMCU esp wifi shield and then i try to connect through te app but it hangs and the error appears. The freelancers says it works 100% 1. Is the problem on the code of arduino and esp sending the data or the delays? ( I attach the codes loaded on them) 2. Is the problem on the app getting the data? Maybe the versions of android or the delays? 3. There is no problem on the system and I connected wrongly the wires? I want someone to inspect the code and fix my problem. I would be happy to work with you, Thank you in advance