12.1.0 and iControl REST and /mgmt/tm/sys/failover/

Hello, following the API reference, I send a POST to /mgmt/tm/sys/failover/, specifying a JSON payload as:

{"standby":true,"trafficGroup":"traffic-group-1","command":"run"}

.

• I receive a HTTP 200 response with expected JSON body in the response, but no failover occurs on F5 system. I have enabled debug on restjavad and it seems as though the transaction is accepted by REST but in LTM logs I do not see any attempt at a failover by SOD. It seems as though the request is accepted but for some reason, nothing is done with it. Am I doing this in the wrong way? Any extra debugging I can enable to shed some light on this? I am about to enable iControl Debug to see if I can get any more useful info.

• The failover works via TMSH and GUI so the setup is ok.