Hello,

It sounds like that the server might be running low on resources, I could suggest starting with checking the server resources utilization. You can do that by following the steps here:

https://www.digitalocean.com/community/questions/how-to-find-the-processes-that-are-consuming-the-most-server-resources

As your database is running on a separate instance, I could suggest checking the resource utilization for your managed database instance as well.

Also I would recommend enabling logging for your application and checking your error log, it is possible that in there you would find more information on why the application is freezing.

Let me know how it goes.
Regards,
Bobby