On Instagram app and website I am having this issue, where when I click the blue follow button so it turns to requested, when I leave their page, and instantly go back to their page the "requested" button disappears and is replaced once again with the follow button. The button works, as the user can still accept or deny my request. However, even if I accidently requested, I have no way of removing it.
Via Quora, none of these apply to me
You’ve exceeded your following limit. Instagram has a limit of 7,500 accounts you can follow. If you’re on that number, you won’t be able to follow another account anymore.
Instagram is preventing you from following/unfollowing accounts. This could happen initially when you set your account up and you follow/unfollow lots of accounts in a short space of time. Instagram will flag this behavior up, so it might take some time for your account to “cool down”.
The user you are trying to follow has blocked you; you’ll therefore be unable to follow this account.