Your config is correct, well at least snapvault part is correct
Did you add fas3040a to NTAP_USERS? You need to add the secondary credentials, that is only thing I can think of, if they are missing you could get this error.
The error just means SC didnt find any relationships for volume on fas6240d, it is a configuration error somewhere.
What would help is seeing rest of config file and also the api results from snapvault-status, are we actually seeing your relationships? You can certainly investigate in the .out file SC creates further, lots of info there.
Yep issue here was snapvault relationships didnt exist on primary only secondary which can happen if you delete baseline snapshot on primary. Since Snap Creator goes first to primary to find secondary we got message that no relationships exist for given volume, which was 100% correct.
After doing a "snapvault stop /vol/volume/qtree" on the secondary for all volumes. Then doing a "snapvault start -S primary:/vol/volume/qtree /vol/volume/qtree" on the secondary for all volumes I was then able to successfully do a snapvault update using SnapCreator.