The Center for Medicare and Medicaid Innovation launched the Accountable Health Communities (AHC) Model in 2017 to assess whether identifying and addressing Medicare and Medicaid beneficiaries' health-related social needs reduced health care use and spending. We surveyed a subset of AHC Model beneficiaries with one or more health-related social needs and two or more emergency department visits in the prior twelve months to assess their use of community services and whether their needs were resolved. Survey findings indicated that navigation-connecting eligible patients with community services-did not significantly increase the rate of community service provider connections or the rate of needs resolution, relative to a randomized control group. Findings from interviews with AHC Model staff, community service providers, and beneficiaries identified challenges connecting beneficiaries to community services. When connections were made, resources often were insufficient to resolve beneficiaries' needs. For navigation to be successful, investments in additional resources to assist beneficiaries in their communities may be required.