The short version of the problem at hand is that "log in using" in File Options does not seem to function in WebDirect. At least, not in this instance. The file in question is hosted (FMS 15), and if I access it by FileMaker 15, "log in using" works just fine, but when I try to login via WebDirect (same machine), it fails: I am presented with a login box.
Has anyone else had this problem? I called FMI's tech support, and the individual said he'd get back to me but did not. If need be, I can post the longer version.