Summarize this article in one sentence.
Consider several of the following points to do some preliminary diagnosis. It may be that a simple correction to the environment can fix the problem with no further effort.  Check the dough and yeast type. Some sourdough cultures are very slow rising and may need several hours to rise. A Make sure the yeast is still within its expiration date.Powdered yeast in packets last a long time, as does storing jars of dry yeast in the freezer. However, both fresh and dried yeast have a lifespan after which they will function weakly, or not at all. The ideal temperature is approx 100°F (38°C) and high humidity. Move too far out of that range, and your yeast will not be happy. Breads made with cake or all-purpose flour, have low gluten and protein contents, so your dough may rise—and then collapse.  This can also happen if you have a dough that has too high a ratio of water to flour. Some flours contain antifungal ingredients to prolong shelf life. As yeast is a proud member of the Fungi kingdom, this will most definitely inhibit growth. Organic, additive-free unbleached white bread flour works best for a good loaf of white bread. Heavier flours such as whole wheat, rye and other types of whole-grain flour will result in a heavy loaf that does not rise as much as fine white bread flour. The pan, banneton, or tray you use will make a difference. Too large, and the dough has nothing to push against when rising, so won't rise upwards. Instead, it will spread and possibly collapse. Small buns do well placed fairly close together. Some spices, such as cinnamon, are naturally anti-fungal.  For sweet fruit buns or cinnamon rolls, you usually want a fast rise, as the cinnamon will eventually kill the yeast off. Some dried fruits also are coated with antifungals as a preservative. Organic dried fruits are expensive but much better for baking. What many bakers do is use standard dried fruit but don't add it till the final proofing. Salt is a required ingredient for developing the gluten proteins that make for a smooth elastic dough, but too much will kill the yeast. Add only the required amount, and add it to the flour, not the water, at the beginning.

Summary:
Find the problem. Check the environment. Check the flour types. Use the proper container. Check your ingredients. Ease up on the salt.