Solved: Bad mask /16 for address #.#.#.#

[chicagotech]

Situation: when trying to assign an IP address to Cisco AP, yo umay receive this error: Bad mask /16 for address #.#.#.#, for example,

chicagotech_2(config-if)#ip address 10.0.20.54 255.255.0.0
Bad mask /16 for address 10.0.20.54

Cause and solution: You may have a no ip subnet-zero command l ine. Adding ip subnet-zero command will fix the problem.