A chain quote is greyed or marked as an estimate

You see: a quote is greyed, or marked as an estimate (≈), and clicking it adds nothing.

Greyed before the open (by design). The quote is indicative. Prices and the risk graph use the last quote from before the gap.

Marked as an estimate (≈). IB sends no two-sided market for that contract. The risk graph values the leg on the estimate, but a click on it adds nothing until a live quote arrives.

What to do: wait for a live quote, or choose a strike that has one. See Add legs from the chain.