Usually, the primary cause of this error is the work disconnection. Accordingly, if you see an error, the first thing you should do is to check your network connection.
Check if your Wi-Fi/mobile data is connected or not. This Instagram error could still happen if the network signal is weak. So open a page in your browser, if it loads slowly, it means a weak network signal. So you might use Instagram later when the network signal is better or switch between cellular data and Wi-Fi data to see which one works better.