When you say that the document is blank, do you mean that the content of the document you uploaded is there, but the values you entered into tags are not?  If so, I think the reason is that the signer has not completed signing and has not committed these values to the system.  There is a setting in your admin console under Sending Settings called, "When an envelope is sent, write the initial value of the fields for all recipients".  When this is enabled, you, as the sender, should be able to see the values you entered for most tag types.  Also, when this is enabled, a signer in the envelope would be able to see the value for another signer who has not finished signing.

https://support.docusign.com/guides/ndse-admin-guide-sending-settings

I have the same problems. I have a .pdf. After I fill out the entire .pdf locally. I upload the .pdf and then send it out for signature and all the fields I filled locally are blank. What is going on?