I don't know if you ever resolved this, but for the sake of leaving my solution here for anyone else to find... here it is.
Modify the file ",serialno" located at the root of the simulation directory of one of the two simulators. The reason it fails, is because it thinks that you are trying to do a sync snapmirror with its cluster node and this is not possible.
Generally this problem is caused by the way sync snapmirror works.
Async snapmirror uses a pull operation from the destination filer. As long as the destination filer can figure out how to get to the source (e.g. by snapmirror.conf and name resolution) then it works fine.
Sync snapmirror starts by using async snapmirror and then once it is close enough it switches to sync. At that time it goes to a push operation from the source, so the source also needs to be able to figure out how to get to the destination (e.g. name resolution)
My suggestion is that you start by checking your snapmirror.conf configuration to see what naming convention you used, then go to both the source and destination filers and check that you can ping via both hostnames. I suspect you will find that the source is failing to resolve the destination...
Thanks for your reply. Please find my answers below.
1. Which ontap version are u using (dest and source)? - NetApp Release 7.3.4
2. Check whether that inspite of this error, updates are taking place or not (do some manual validation in the destination)!! - A second mirror happened after the intital mirror. After this mirroring didn't work and i am receiving this error in the console "SnapMirror: destination transfer from simulatorclone:snaptest to mirrorvol : Error in snapmirror sync mode negotiation."
3. Though ur snapmirror intialization successfuly happened, just do a quick check that ur destination volume is 10Gb and free space is there(sync snapmirror needs that i guess) - My destination vol is of size 9 GB. What i heard is destination vol size should be more or equal to the source volume size.