Not shop STL Print issues - HELP?

I downloaded a bunch of items from the Not shop and sent them to craftCloud for printing - they have responded with the following message and images below:
PS, I have not modified any of the STL files (**Button+Pusher±+3D,
Dust+Hose+1.25, Triangle+Anchor±+3, Belt+Guard) - print settings **
Material — SLS Nylon PA12 (SLS) - Finish — Shot Peened - Colour — Dyed Black

Any pointers?

Reply:
”*After reviewing your order, we found the following issues:
The walls of your model are not thick enough. This may lead to fragile parts breaking during printing and/or shipment (please find a picture attached). We recommend a minimum wall thickness of 1.0MM.

It’s our goal to help you get your order printed with satisfactory results, which is why we would happily process the order if you send us a revised model in reply to this message. If you are aware of the issue mentioned already and you are willing to accept the predicted results, we will proceed with the order accordingly.

If you need help editing your file, we can recommend the following article by All3DP”*