If you have forgotten your password, you can press “Need help with login?” during the login process. Here you can choose email, if you linked a valid one to your account. You will then receive an email with a link so you can change your password.
Unfortunately, it is not possible to log in through Instagram or Twitter anymore.
If you do not have any valid backup-method connected to your account and you have forgotten your password, you will not be able to log in. If that's the case for you, please remember to add an email address to your next account!