Hello, I am working on the options strategy, in my backtesting I see several errors like this:

2019-04-22 09:31:00 : The security with symbol 'WDFC 190517C00180000' is marked as non-tradable.

I don't understand why this contract is non-tradeable, its expiration date looks correct, is there other reasons for that? 

Also, how can I detect this in my code? I cannot see any field that would mark the contract as tradeable or not. It seems the only way is to place an order and handle fill error, but this is far from ideal.


Even more weirdly, when I tried to isolate this in separate project (I cannot share the original code), it does sell the contract, although with a warning about stale price. So I'm really not sure about the nature of this problem.