If you try to send an already signed document and receive the error "Cannot sign already signed document". Then this guide can help you.
The error message is due to the fact that the document has already been signed, which means that the document cannot be overwritten with new signatures. In addition, it will overwrite the digital markers that ensure the validity of the document. This will mean that the data behind the scenes, such as IP addresses and master data will disappear.
We recommend that you obtain all signatures for each document to be signed. This ensures that everyone has signed to the same terms. You may find it useful to see the guide here on adding more signers.
If you are unsure how to check if your document has been signed, you may find this article useful. The article describes how to see if a document is protected, and shows the solution on how to remove these protections, so you can still send a document, with signature stamps, but without the underlying data that is the obstacle.