Are you are stuck on iOS 10.2.1 or higher, having missed the iOS 10.2 signing window and therefore the Yalu jailbreak? If so, you may be in luck today, provided you have the correct setup. Early reports have come in that some devices are creating nonce collisions on iOS 10.3 b1, providing an indirect route back to iOS 10.2 through Prometheus.
For this clever workaround to come off, you must have a device which produces collisions, namely the iPhone 5s or (possibly, though not confirmed on iOS 10.3 b1), an iPad Air. If you do, you may be able to downgrade from iOS 10.2.1 to iOS 10.2 and jailbreak, by first downloading and installing iOS 10.3 beta 1, and then downgrading to iOS 10.2 using futurerestore.