Layers of design work individually, but not together

Hello all!

I have a Singer SE300 and I have been teaching myself ink/stitch. Over and over again, I get the error symbol on my machine from the designs I have created. I can not figure out what I am doing wrong!.

The design I am currently working on has 6 colors and my machine is willing to sew each layer individually but when I export them together, it errors out. Anyone know any tricks?

I have spent weeks fighting to figure out what causes the machine to error and I have no leads. Sometimes the designs will sew and sometimes they wont.

Please give me any advice you have for troubleshooting. The designs always look good in perams and the simulator.