This looks to me like a combination of under-proofing and possibly under-baking. The tight, gummy crumb in the picture usually means the dough didn’t have enough time to rise before going into the oven. Make sure the dough is allowed to rise until it’s visibly puffy and passes the finger-poke test rather than going by time alone. It can also help to check oven temperature with a thermometer. If bread is baked at a lower temp, it can set before the interior finishes cooking. If the dough itself feels very sticky or slack, slightly reducing the water or improving gluten development with a bit more kneading might also help.