Is this is a standalone plan where the plan sponsor is not part of a controlled group, and there is not a large group of employees excluded by classification? If yes, it is unusual that deferrals would fail coverage, and slightly more likely that match also would fail coverage in which case you may want to take a closer look at the test. If no, then the coverage testing starts to become orders of magnitude more complicated and you may want to engage a third party to help guide you.