Nothing. App is based on Node.js so you won't need apache or any other PHP services. If you already have a VPS running other services you can still use this app if you have root access to install Docker.
This error happens when your apk application id or fingerprint doesn't match what has been entered on firebase console. Make sure of those two being correct and generate new
google-services.jsonand try again in a few minutes.
This could happen if firewall is not open for the ports used by app for external connections for example you can open port 8080 using these commands:
sudo firewall-cmd --zone=public --add-port=8080/tcp --permanent
sudo firewall-cmd --reload
sudo ufw allow 8080
Most of the time it is due to a misconfiguration in Maps API key provided for Backend App. Check it's own section for having correct configuration in terrms of Billing, Library and restrictions.
If file uploaded as Firebase Private key is not private key file and some other file this could happen. Easiest way to resolve this is to clear out server and reinstall app.
With docker installation mode mysql gets installed automatically. If app can't find it usually it means due to lack of memory in server MySQL container was stopped. Make sure VPS has at least 2GB Memory and restart the services.
Most probable reason for this is system reboot. Some hostings migh ocassionaly reboot their servers (Best ones do this a lot less maybe once in a year or less). In case of reboot following command would restart the app services
docker-compose up -d