When you upload your 3D model, and it has errors that need fixing, our software will attempt an automatic repair. If these errors cannot be resolved automatically, you can submit an offline price request, which is free of charge. Our customer service team will then assess your 3D model, and if it has minor imperfections, they'll take care of the necessary adjustments for you. Once that's done, you'll receive a link to proceed with ordering the model.

In the event of significant design issues, we will advise you to redesign or modify your 3D model and upload it again. To ensure a flawless outcome, we recommend taking a lot at our design guidelines. 

You might also be interested in the article: How can I design a model that is 3D printable?