Quick placing signature requests on a signature spot is not working on web version.

Hi, I used to be able to place a signature request quickly on a document's signature spots from the web version. Suddenly, it does not allow me to place the signature request spot. The signature request box is still showing up, but when I click it, it does not drop the signature request box on the document. My only option is to do "Advanced editing on". What's problem with simple editing function?