Digital Signature not showing up as fillable field when recipient receives document

I have set up a fillable document and have signature fields set up as digital signature (I can see it on my copy of it that it is fillable and digital signature needed); however when recipients receive the email with the PDF all of the fillable fields show up and are able to be completed but the digital signtuare fields do not show up as fillable or required so they cannot sign it. How can I get this fixed so the party can not only complete the other fillable fields but also complete their digital signature. Thank you