A method, at a network element in a network, said network element being a network controller, the method comprising: receiving a first notification indicating that a first packet of network traffic associated with an application and traversing a service chain in the network from a source to a destination has failed a service chain verification in a network, the service chain being a network path; triggering a data-collection feature on one or more nodes of the service chain in the network for second, subsequent packets of said network traffic that traverse the one or more nodes, the second, subsequent packets having the same source and destination as the first packet, wherein the data-collection feature includes a packet tracing feature applied to a second, subsequent packet, the data collection feature augmenting the second packet with metadata about the one or more traversed nodes or the network path; receiving a second notification indicating the second, subsequent packet failed the service chain verification in the network, wherein the second notification includes packet trace information related to the second, subsequent packet traversing at least one of the one or more nodes of the service chain in the network, wherein the packet trace information includes a failure condition that caused the second, subsequent packet to fail the service chain verification; evaluating the second, subsequent packet that includes the metadata augmented by the data collection feature; and identifying a cause for the first packet to fail the service chain verification, the identifying based on the failure condition included in the packet trace information associated with the second, subsequent packet. receiving a first notification indicating that a first packet of network traffic associated with an application and traversing a service chain in the network from a source to a destination has failed a service chain verification in a network, the service chain being a network path; triggering a data-collection feature on one or more nodes of the service chain in the network for second, subsequent packets of said network traffic that traverse the one or more nodes, the second, subsequent packets having the same source and destination as the first packet, wherein the data-collection feature includes a packet tracing feature applied to a second, subsequent packet, the data collection feature augmenting the second packet with metadata about the one or more traversed nodes or the network path; receiving a second notification indicating the second, subsequent packet failed the service chain verification in the network, wherein the second notification includes packet trace information related to the second, subsequent packet traversing at least one of the one or more nodes of the service chain in the network, wherein the packet trace information includes a failure condition that caused the second, subsequent packet to fail the service chain verification; evaluating the second, subsequent packet that includes the metadata augmented by the data collection feature; and identifying a cause for the first packet to fail the service chain verification, the identifying based on the failure condition included in the packet trace information associated with the second, subsequent packet. <EOS>