Turn your Instant Pot to the sauté setting. Chop the onions and add them to the pot with the butter and the salt.
While the onions start to cook, chop the celery and add that into the pot.
Do the same with the carrots, garlic, and potatoes, stirring them while they sauté so all the vegetables cook evenly.
Add the tomato paste and stir to coat the veggies.
Add the corn, the stock concentrate, the water, and the bay leaves, and close the lid of the Instant Pot making sure it is in the sealed position.
Turn the sauté function off, and set the Instant Pot to pressure cook on high for 10 minutes.
Tip the canned salmon into a bowl and break it up into small pieces. You can remove the larger bones if you like, but they are totally edible (and very nutritious).
Turn the Instant Pot off, release the pressure, then remove the lid and stir in the sour cream and the dill.
Once the sour cream and dill are fully incorporated, add the canned salmon pieces, put the lid back on and leave it alone for 5 minutes. This will allow the residual heat of the soup to heat the salmon to heat through.