Signature & initials disappeared, no option to add again

Hi there

I'm using AA Reader DC on a Macbook Air and am struggling with the Fill & Sign function, specifically the signatures. I have been using Reader DC's Fill & Sign  function successfully for ages to sign and initial documents but today both my signature and initials have disappeared. And... there is no option to add them again. Please help!

I'm using version 2019.010.20099

Screenshot below.