Can the developer block the application?

Question

Java

The story is that I use cms crea8social (Nigerian developers)
I needed an Android application for a social network, I decided to buy from them, the source code itself was not sent, only the apk file with a terrible interface without translations, I had to redo it because it's a shame to expose people with such a wrapper, I started asking them to replace at least the languages, but they wanted a separate fee ... forgetting about them, I deployed the application through apktool, changed what I needed, collected it, signed it and everything was fine, but today I see an event in the app_clear_data firebase console from Nigeria
and in the application not included writes check your internet connection
Can the developer somehow block the application? How to fix it ? or this question
Is this related to the server change? yesterday i changed server from hetzner to regru
please help your ideas and suggestions .. thanks

Answer 1

Is this related to the server change? yesterday i changed server from hetzner to regru

check which IP is knocking on, draw conclusions
with app_clear_data, there may be protection, again due to a server change