Christian Chat App not available

I've been using the Christian Chat app for years now and enjoyed getting in contact with other christians over there. Sadly, when I open the app nowadays, it doesn't work anymore (I can't even see my own username in the app). I've already noticed this months ago, but back then the app was most of the times working a couple of hours later or at least on the next day.

Is there a reason why the app is closed most of the time?

Google Play Store warned developers that if they don’t update their apps
for some time, the app will no longer be displayed on their site. So
the reason it is not working could be because of lack of updates.

I did find this link in anther thread about it, but since I have not used the chat
rooms since just after the platform change of 2018, I have no idea if it works...

https://apkpure.com/christian-chat/com.christianchat.app

There have been many threads about it, mostly asking why it's not working.