Hi Scapers,
We're aware of an ongoing issue causing some players to be unable to login to the game.
Our team have been working hard to get this resolved as soon as possible. We'll keep posting all the latest updates on the situation in news post.
While various potential workarounds have been mentioned in the community, we want to stress that we highly recommend you do not remove any form of account security (including authenticators). We have verified this is not the root cause of the issue and you should not compromise account security.
Thanks for your patience. We'll get you playing as soon as we can.
The RuneScape Team