RET191133 – Invoice already exists with different CTIN or same CTIN. Please delete the existing invoice and re-upload again.
This error is from GST side.
It might happen that the you are uploading the invoice which is already present on the portal.
You need to check whether the invoice has been already uploaded on the portal or not.
Check that there is no change in invoice data between what was uploaded and what you are now trying to upload.
If the invoice is uploaded, then just avoid the error and do not make any changes in it.
If changes are to be made then the old invoice present on the portal must be deleted first.
Then upload the amended invoice with correct JSON file.