Before making any changes, try restarting your network devices: Turn off your router and modem. If your DHCP issue persists, move to Step 2. This guide provides a detailed step-by-step process for diagnosing and resolving Dynamic Host Configuration Protocol (DHCP) authorization failures in an Active Directory (AD) environment. The automatic assignment is handled by the Dynamic Host Configuration Protocol. Did you try connecting the PC to directly to the DHCP switch and check if it get the ip address? Also have you issued " service dhcp" to enable DHCP service on switch? Regards Najaf Please rate when applicable or helpful !!! 01-05-2013 11:24 AM Hi Mahesh, if the 3rd switch also has an IP address in. we are using cisco catalyst 9300 stack as core switch. DHCP is configured in core switch. IP lease pool is full – The router has run out of. Have you been tracking the number of client addresses against your address pool? Is the office hosting an open guest wifi, and positioned close to another business which might have a walk-in volume? Do you know how many IP addresses are expected per user? Are your lease times too long? Is the.