This phase I trial studies the side effects and best dose of PI3Kbeta inhibitor AZD8186 when given together with docetaxel in treating patients with solid tumors with PTEN or PIK3CB mutations that have spread to other places in the body or cannot be removed by surgery. PI3Kbeta inhibitor AZD8186 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as docetaxel, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving PI3Kbeta inhibitor AZD8186 and docetaxel may work better in treating patients with solid tumors.