I have a server that runs ubuntu 20.04, we have a web application installed on. But two of their features take a lot of times to complete. However, they were running well since few weeks.
What changed? Are you certain that nothing with the application changed? Or what about the network? Or the client connecting to the server? If you can eliminate all of those possibilities, then it might be something to do with the base server. You could look at your apt logs and see what has been updated and you might be able to figure out what the culprit is. There will probably be a fair amount to wade through, so that’s not going to be easy. For those reasons, I’d start with assuming the server is not the issue.
The problem is that when a user performs certain tasks within these two features, the requested page always takes at least 15 minutes to load. And a week before that, it wouldn’t happen.