My sourdough baguette doesn't rise at all

I used my 6-hour old starter to make the baguette. The mixture of the starter and flour rises well. I did warm fermentation at 25C and cold fermentation over night in the fridge at 2C. In the next morning, during the dividing and shaping, my baguette doesn't rise at all and during proofing, the dough becomes flat and sad. My room temperature is 26-29C. Finally, when I put the dough into the oven, they never rise and the baguette look like a flat wooden stick. I wonder if the problem is my shaping skills. Any advices?