Why does my soup smell bad?

I made a vegetable noodle soup with corn onions and a bunch of other vegetables. I didnt add corn starch since i was trying to be healthy. However even though im just done cooking it, the soup smells bad? Did i make a mistake while cooking? or did I just forget what soup smelt like?

what I did:-

Heated the pot - Added garlic and olive oil - Added the veggies and sauteed for a while - added the water - let it simmer till tender - added the noodles and let it cook - added salt, pepper and a bit of chilli flakes

Where did I go wrong😭