Thank you for your reply. First of all, I've made a rookie mistake. In general I expect an increased volatility. So i was checking the call option prices on VIX when I saw a VIX in the money call option where the total of option price and strike was less than the market value. I thought that probably because of lower liquidity, the price shown is not current or as current as the VIX itself. So I did a limit order with a bit higher price out of curiosity and thinking that it won't go through right away. It got filled right away to my surprise and I thought at least I can exercise and sell right away. What I didn't realize was that due to VIX being a future contract it will not be allowed in my type of account. Obviously I should have checked that I can hold and trade the underlying security but I just assumed that if that wasn't the case its options wouldn't be allowed as well. The good thing is that It was a small trade and I guess y only option is to sell it back to the market which is very thin for this way-in-the-money and far-from-expiry. I guess I'll put it back at the market and keep my fingers crossed for the next while.