FreeNAS-11.3-U4.1 copy large files error

[caver99]

i have a server running FreeNAS-11.3-U4.1 and have 20tb storage and i can copy files to the share fine but if i attempt to copy a large file like an iso of a dvd it failes with error saying i need permission to prefore this action which is strange because i have full access as i can make folder, copy files, delete things so not sure where i need to look now.
the system is a dell poweredge r720 and im running direct on the hardware no vm.

 

[caver99]

ive checked all the settings and i cant see any reason for it to not allow files over 2gb as its on zfs

 

[caver99]

i installed win 10 on the drive and i can copy files over 2gb no problems so its definitly an issue with freenas.
and i cant belivie no one can help me with this