Are you asking the reason why the electronic invoice download failed to display the signature? The reason for this is the following：

1. Is the failure of electronic signature due to network reasons or the failure of the signature verification system of the tax bureau? When the invoice is uploaded on the network, the digital tax certificate will be invalid during the process of adding digital signature to the electronic invoice, and the verification system of the tax bureau will also fail.

2. Software setup problems. When setting software parameters, there will be some omissions, such as certificate, certificate password, signing institution and other information errors, which will lead to signature failure.