Cannot digitally Sign document

[Doxa31390318mwq2]

I have paid fro acrobat pro, and I am trying to sign my document. I have filled out the whole thing but now trying to sign my document it's not letting me sign it. When i click the tab "fill & Sign", the options to sign myself or to request an e-signature come out blank (unclickable). I have been stuck on this for days and I don't know where to go for help! 

[Abambo]

What do the document properties say (Ctrl/Cmd D)?

[Doxa31390318mwq2]

i've just checked and it shows 'Allowed'. IT still wont show any of the options in the 'Fill & Sign' tab to be clickable. they are all greyed out