Can you post the recipe? If you're over 10k feet you may need to adjust for altitude, but there's likely something else going on. Is your flour fresh? Are you using active dry or instant yeast? Instant yeast doesn't need to be soaked in water first, so that'll eliminate any potential issues with water temperature. Are you kneading by hand or with a stand mixer, and for how long? You shouldn't need bread flour unless you're making sourdough, as long as your AP flour is fresh, but whichever flour you use, you'll need to be sure you're kneading it enough to develop the gluten. After you first knead it, before letting it rise, is the dough smooth or does it look like batter? If you tried to pick up a piece of it, would it come away easily from the rest of the dough, or try to stay in one ball with the rest of the dough? One thing to use when determining if you've kneaded long enough is the windowpane test - you should be able to pick up a small piece of dough and gently stretch it enough so that you can see light through the other side, without the dough tearing. If it tears, it needs more kneading.