If you are trying to log into your WordPress website and you are seeing a 'Forbidden 403' error message, this means that automatic 'brute force' protection has been invoked to stop any further attempts at logging in. This is a security precaution and could have been inadvertently triggered if you have tried too many times to log in with either the wrong username and / or password.
The 'Forbidden 403' error message is just temporary. The brute force protection will expire after five minutes after the last incorrect login attempt.