There is a lack of FIAT-IGNIS Gateways. In the past, our Changelly Widget sometimes worked for FIAT-IGNIS conversions but since a few months, this is not a valid exchange pair anymore.
I see that ChangeNOW.io has Ardor, but why no IGNIS? Technically it should be the same?
It's not because the ways are technically different.
Exchanges like Changelly and ChangeNow don't trade themselves. They use APIs of big exchanges and provide the rate they have at the moment of a trade. They don't have their own market.
Ardr is available on Binance, but unfortunately Ignis is not. I assume that's why Ardor is able to trade on ChangeNow, but not Ignis.
As of now, there's Ignis-fiat-gateway on Jelurida's webpage via Simplex.