I have just done a design on an RS1800 but when I try to share it, I get an “error communicating with the server” message.
I was able to share a different design on a Lamborghini at the same time without any issue.
All the logo apart from the Ford logo (which is from manufacturers section) are created by me.
Error communicating with server probably indicates something other than your design being the issue. Save it, restart your Xbox and try to share again.
Rebooted and resaved the design and it still doesn’t work.
I even erased all the decal and just painted the car white and it wouldn’t let me share even that!