Search for their username in Instagram
Check whether their profile still appears in search results
Open old direct messages with them
See if their profile photo and name still show in the chat
Tap their profile from the chat and check if it opens
Look for a message saying the user is unavailable or the page is unavailable
Try viewing their profile from a different Instagram account
Check whether their posts, reels, and follower count are visible
See if you can tag or mention their username
Try following them again if their profile appears
Check whether your comments or likes on their posts are still visible
Look for sudden disappearance of their profile from your following or followers list