Also on Instagram there are problems with access to user profiles and for almost the same reasons as the rest of similar social networks: loss of access to email or the phone number used to create the account on that social network, making it impossible to reset the password.
In these cases, the only possibility is that the affected user has associated their Facebook account, but unfortunately this does not always happen. Contacting Instagram as suggested by many tutorials published on the web could not be considered a solution either, since the social network does not contemplate this situation within its rules of use.
Therefore, today the only real solution is to try to recover the email or phone associated with Instagram and thus be able to reset the password. Fortunately, each email provider makes various account recovery methods available to their users. For more information, check out the following tutorials: