It is rare, but it can happen than your iOS smartphone or tablet keeps asking you to set your passcode (PIN code), even though you have already done so. This is pretty inconvenient, because you are obliged to use a PIN in the iOS app, so you will not be able to use the messenger.
After some research on our side we have discovered that the problem stems from your Apple account. If you sign out of your Apple account and back in, your account should once again be able to send our platform a signal about your passcode. As soon as you have done this, you will be able to use the messenger again.