Merchant Shipping Group invalid

Hello,

We’re trying to start up EFN again, so I was listing a test listing in our Germany marketplace.

I had almost finished the listing and saw that the Merchant Shipping Group field was flagged. I’ve never filled this in before so I’m not sure what is required, also it only had one option to select which was ‘Invalid’.

Can anyone tell me what this is/what I need to do?

Thanks!