If you enabled TFA, go to https://www.runemate.com/community/account/two-step Introducing Two-Step Verification | Community | RuneMate
You've been given a private/secret key, correct ? Did you set-up your authenticator using that key ? If you used email authentication it will only work with the website, which means you will need to enable App authentication to work with the RuneMate client. Then use that private/secret key to generate a new temp key for use with the client.
