Can vegetables be roasted at lower temperatures?

Can vegetables be roasted at lower temperatures?

I tried to bake some new potatoes, small tomatoes and hot peppers, in
extra-virgin olive oil, using a recipe calling for 1 hour at 100° C.
I was skeptical of the 100° C temperature, so I set the temperature to
120° C instead. However, even after 3 full hours of roasting, the
vegetables still had a raw tang, and the texture of the potatoes was a bit
rubbery.
What could have been the problem here? Is 120-140° C too low for these
vegetables?
(Note: At one point I turned on the ventilation mode, and it seemed to
start cooking much faster - maybe even a little too fast. Could the recipe
have been intended for a convection oven?)