Are yu use Shared Hosting or VPS ?
1. If you use shared hosting, Shared hosting administrator system will stop the service running of Node.js. Why? Couse recognise an anomali process and abnomal. Thats policy of shared hosting.
2. If you use VPS or Cloud VPS, double check the configuration of node.js. If still same, try reinstal it from begining. After that, try PM2 for running process of node JS. for what? PM2 it for help you running whatsapp.js and app.js ALL DAY and you can monitoring the node.js proccess.
3. If you use Cloud*lare for DNS record, check section firewall and setting up with your ecosytem. Sometimes is block the connection of domain.
4. Consider of firewall of your hosting/vps, sometimes is detect an malware process and make your script/apps doesnt running.