They may have rotted. They should not be planted below the surface of the soil either, so if you cannot see the rhizomes, they were planted too deeply. I would dig them up, and if you see black or brown rot, you can cut the rotted part off, let what's left of the rhizome dry out at the cut, then replant with the rhizome at the soil's surface so its back shows, and water sparingly. You may be able to bring them back, but they won't bloom this year.

Thank you @hosenemesis for your response and advice. I will see how badly the rhizomes are affected. What should I do about the other pot of irises that seem to be doing ok? should i dig them up and plant them closer to the surface?

I wouldn't bother- you can scoop out some of the dirt at the top if you wish, but I wouldn't disturb the roots. Good luck!

I planted mine too deep, out of 12 i got 5 sprouting. I followed a YouTube video on how to plant them. (I won't do that again!)