The bread I make in my bread machine falls conitnually. It didn’t always do this,but it started one day.?

This is most likely due to two possibilities.

Most likely will be too much liquid. You may have used precisely the amount called for in the recipe, but used AP flour instead of bread flour — AP flour cannot absorb as much water as bread flour. Also, too much water helps yeast grow faster, causing an over-rise which collapses during baking. Too much oil can prevent a good gluten network from forming, but that usually means less rise in the first place, rather than a collapsed loaf.

The other possibility is too much yeast, in which case essentially the above described over-rise and collapse situation can occur.

There are other possibilities, but those cover 90% of the situations.

Oh…almost missed a big one: high altitude situation, where many bakers are told to increase water in recipes, when they ought to be reducing. The idea that more water is needed is based on the drier air, but the fact that the air pressure is lower (remember how water boils at a lower temp at higher altitudes?) means less yeast will provide the same amount of rise. Sounds like I am mixing up the previous answers? They are all inter-related! Less yeast in this situation would provide less rise…OR…less water would reduce the yeast activity thus less rise. Both should work, depends on your situation and recipe. Remember, the flour and yeast are competing for the same water, so you have to balance which you need to reduce. Take notes on what works better.

Hope this helps…