The document has got missing parts (signature, logo)
There is no company logo on the invoice
Please make sure that the logo is chosen and visible in the plugin settings:
Please check the filepath to the image and make sure that the file really exists on the server. You may also try to remove it and choose the logo image again.
There is no signature on the invoice
Please enable the Show Signatures in the plugin settings and make sure that there is the right username chosen in the dropdown:
Please edit your WordPress user profile to adjust the visible name.