Some causes, like update problems, might cause apps to go rogue or behave erratically. Clearing the Instagram app on your iPhone can assist ensure that this isn't the cause of the app's misbehavior. Clearing or force-closing the app removes any problems or bugs that may have caused the app to malfunction and stop performing as expected. Here's how you do it:

• To open the app switcher, press the Home button twice fast. It will show you previews of the applications you've recently used but haven't closed.
• To dismiss the Instagram app preview, swipe up.
• Swipe up on individual applications, as you did with the Instagram app, to remove additional background apps.                                                                                                                                                                                                   After deleting Instagram and background applications from your iPhone 7 Plus, follow these steps to do a soft reset or restart:
• For a few seconds, hold down the Power button until the Slide to Power Off command displays.
• To totally turn off your gadget, drag the slider to the right.
• To turn on your iPhone, press and hold the Power button for 30 seconds.

Allow your smartphone to finish booting up before attempting to access the Instagram app again to check whether the issue has been resolved.