If you’re getting a direct error about OAuth, your IP has not been blocked. There are many reasons OAuth can go wrong, most of them detailed within the OAuth documentation on this site. Some basics are to make sure that if you’re using a device or simulator, that the “current time” is accurate and within at most a few minutes of the server time on api.twitter.com.
This error in particular indicates that your signature is correct but that the credentials you’re presenting are in some way not valid for use. At which step are you receiving this error? Have you already negotiated an access token?
