If i force carb i chill the beer as long as i can then set it to 10 psi, no more. gently shake my keg for around 10 mins then release the pressure. Set the pressure to serving pressure and its usually ok. I have force carbed at 30 psi and all i got was froth. Might be best to leave your pressure relief valve open, But covered with a plastic bag or something, for a day or two, reset serving pressure and then retry. Sounds like too much c02 in to me.
You tube has lots of videos about setting to 30 psi but ill never make that mistake again.