I thought I’d leave a comment in case it’s useful for anyone… if the oauth_timestamp is too out of date, Twitter returns the same “Failed to validate oauth signature and token” error as when you compute the signature wrong in the first place. In my informal tests, future timestamps were okay, but a timestamp older than about 900 seconds results in the error.
If users are reporting problems intermittently, perhaps have them check their system clocks.
Twitter devs, if the OAuth spec doesn’t somehow disallow it, a more specific error message could save a lot of head scratching and many hours of frustration…
