Which airport was paralyzed by the volcanic eruption in Indonesia?

It was Denpasar Airport on Bali - they closed it because of the Agung volcano eruption. If you were planning to fly there, I'd suggest contacting your airline right away about rebooking or getting a refund, most airlines offer that option in case of force majeure. How long the closure lasts depends on how intense the eruption is and how much ash is in the air - it could be anywhere from a few hours to weeks, so keep an eye on the news specifically about the airport or check with your airline.

Have you tried contacting the airline yet or are you looking at options online? When this happens in Bali, they usually close the airport for a few days or weeks depending on how intense the eruption is and how much ash is in the atmosphere. Besides the standard rebooking, you can ask the airline for a voucher instead of a refund - you can often use it for a different route later or sell it on secondary sites with a small discount if you're not in a rush to get your money back.