“We tried something like this before and it didn't work.”
Why they say it. A past failure created scar tissue and a strong bias against repeating the mistake. They are protecting themselves from being burned twice on the same bet.
Do not: Do not dismiss the prior failure or promise you are completely different without understanding what actually broke.
I do not blame you for being cautious, getting burned once is enough to make anyone gun shy about the whole category. What would help me most is understanding what specifically went wrong last time, because most of these failures trace back to one or two root causes, not the idea itself. Can you tell me what broke, was it the rollout, the fit, or the support after the sale?
Then ask. If the exact thing that failed last time were impossible this time, would you be open to looking again?