If you're not getting Instagram notifications, you can miss these notifications due to changed settings, do not disturb modes, and various other reasons.
Check your Internet connection- connect to a faster Wi-Fi network or switch to 5G for better cellular speeds.
Verify that your iPhone is not in Do Not Disturb mode or a Focus mode that silences these alerts.
Make sure you have enabled the Instagram app to receive notifications and enable messages from individuals and group chats
Make sure your notifications aren't paused or in sleep mode.
Check if the conversation is on mute. Like the Messages app, you can choose to mute individual Instagram conversations.
Make sure you have not restricted the particular account
Turn on Background App Refresh. This ensures iOS apps can refresh and fetch new content easily even when they are not on the screen.
Finally, update or re-install the Instagram app, and ensure your account is secure, your password is strong, and your email is on file.
Other additional Instagram tips to schedule messages, read receipts, and more.