There are several possible solutions. The bread may have been left in the bread pan too long after baking. Remove the bread from the pan sooner and allow it to cool. Try using more flour (a tsp. at a time), or less yeast (1/4 tsp. at a time), or less water or liquid (a tsp. at a time). This could also be the result of forgetting to add salt to the recipe.
- The sides of the bread collapse and the bottom of the bread is damp.