What does the message "NG combo with negative capable legs are not supported" mean?

A combination  order is a special type of order that is constructed of multiple separate positions, or ‘legs’, but executed as a single transaction. The legs of the combination may be comprised of the same position type (e.g. stock vs. stock, option vs. option) or different position types (e.g. stock vs. option). It i important to note that many combination order types, while submitted via our trading platform as a combination, are not native to (i.e., supported by) the exchanges and therefore may not be guaranteed by us. Accordingly, our policy is to guarantee only Smart-Routed U.S. stock vs. option and option vs. option combination orders…

Overview: 

Provides information about multi-leg orders specifically relating to guaranteed vs non-guaranteed orders…

When you see the message "No opening trades: ineligible PINK stock" it means an opening order for that contract is not allowed, even if your account has trading permissions for US Penny Stocks.

Additional Information…

The message refers to who cancelled the order. As an example, Cancelled by System is a message you will see when one OCA leg of an order is canceled by the User then the IBKR system will cancel the other leg of the OCA Group. The message for the first leg will be displayed as User Cancelled as the user acted to cancel the order.  The other OCA leg message will show Cancelled by System as the IBKR system was active in cancelling that order. An Invalid Order means the order was either created incorrectly and when submitted the IBKR system would not accept the order. Or the Invalid Order was created in a manner the exchange would not accept or a change occurred like the contract expired so the exchange could no longer hold the order…