Cannot digitally sign document on ubuntu 17.20, LO

I’m attempting to digitally sign a document on ubuntu 17.10, Libreoffice
I bring up the document in writer. I select File->Digital Signatures->Digital Signatures.
I am presented with the “Digital Signatures” dialog box.
I select the button “Sign Document”.
Another dialog box is presented, with the title “Select Certificate”.
I see no Certificates listed in the dialog box.

Kleopatra displays a number of certificates.

When I perform the same procedure on Windows Pro 7 using Libreoffice
the Select Certificate dialog box is populated with various certificates. I can
select the certificate from the dialog box and sign the document.

Any ideas why “Select Certificate” dialog box contains no certificates?
Thank you.

Same issue in JunoBeta. Tried with tutorials, didn’t work, except by creating a rudimentary certificate in terminal, described here
Tried this procedure, and this procedure to no avail, even havin LO pointing at folder.