While configuring the VRF Selection feature, you get an error message after typing the below statement: Router(config)#no vrf selection source 172.16.0.0 255.255.0.0 vrf VRF1 Which action caused this message?

The command no vrf selection source 172.16.0.0 255.255.0.0 vrf VRF1 is used to remove a previously configured VRF selection entry from the global routing table. This entry maps traffic with a source IP address in the 172.16.0.0/16 network to the VRF named VRF1. If this specific entry does not exist in the configuration, the Cisco IOS XE software will generate an error message because it cannot delete an entry that is not present. This is standard behavior for removing specific configuration lines that do not exist.

A. An inconsistent IP address and mask would typically generate an error during the initial configuration of the entry, not during its removal.
B. This describes a conflict at the interface level. The command shown is a global configuration command, not an interface-specific command.
D. The VRF Selection table is an inherent part of the feature; it does not need to be explicitly created. The vrf selection source command populates this table.

1. Cisco IOS XE IP Routing: VRF-Lite Configuration Guide, Cisco IOS XE Gibraltar 16.12.x - VRF Selection Based on Source IP Address.

Reference: In the "How to Configure VRF-Lite" section, under the sub-section "Configuring VRF Selection Based on Source IP Address," the guide details the vrf selection source command. The no form of this command is used for removal. Standard Cisco IOS/IOS XE command-line interface (CLI) behavior dictates that attempting to remove a specific configuration entry that does not exist will result in an error.

2. Cisco IOS XE Software-Defined WAN Configuration Guide, Cisco IOS XE Release 3S - Configuring VRF-Aware Software Services.

Reference: The "VRF Selection" section explains that vrf selection source is a global command to map traffic to a VRF. The document states, "To remove a VRF selection entry, use the no form of this command." This implies that an entry must first exist to be removed. An attempt to remove a non-existent entry is an invalid operation, thus causing an error.