Not receiving notifications from a specific app

Recently, I decided to “Reset all settings” on my iPhone as I heard that it could help settle the issue of a muffled microphone (especially on iPhone 7 Plus). So when I did that people started saying I sound more clearer over the phone, which I was happy with. But then I realised that Instagram (an app I frequently use to keep in contact with some friends and family) stopped sending me Push notifications on my phone. I found that I would have DM’s that were sent to me from hours ago that I had no idea that they were sent unless I go onto the app to see the notifications. I have tried deleting the app and allowing the notifications again and also going to the notification setting on Instagram to see if anything has been turned off, but nothing has worked.

Any solutions?

Kind regards