["Sorry, you're not a police officer!" ERROR]

Sell the current car. Then buy it again. Dont change nothing. Becuase if you even have the police skin or the sirens/beacons on you will get kicked. Make sure that your playing on EU2 or on another server what is not EU1

[PING]

I think this should work. Works for me. Try getting your task manager out. Then just go onto Steam Client Boostrapper and press DEL (delete) and if it asks for permission then press yes or confirm. And do the same thing to your game. Then don't launch steam. Launch your game then it maybe works. I don't know. Just try it. It may help.

[Lags]

Try reinstalling? Lower settings for game quality/graphics? Have you tried these solutions?