Mr Derek izzard

If there was hot before you changed it and now there isn’t, I would imagine it’s because the valve is still closed off for the hot water. If not then check your boiler and see if your pressure bar is stable.

It could be a few things. First, check if the valves under the sink are fully open; sometimes one might be partially or fully closed. Also, check that the hot water hose isn't kinked. Look for any signs of leaking water under the sink. Finally, check if there is hot water at the other taps in the house to determine whether the problem is isolated to this location or affects the entire plumbing system or the water heater.