getSearchForm returns null when using UserSearch in XMPP with aSmack

I have this code, almost unmodified from examples:

                UserSearchManager usm = new UserSearchManager(conn);
                Form searchForm = usm.getSearchForm("search.myserver.com");
                Form answerForm = searchForm.createAnswerForm();
                answerForm.setAnswer("Username", true);
                answerForm.setAnswer("search", contact.getJid());
                ReportedData data = usm.getSearchResults(answerForm, "search.myserver.com");

This works perfectly in a Desktop environment, using Smack library, but I can't get it to work in Android (where I have to use asmack).

The problem is searchForm is null because getSearchForm returns null. This seems to be pretty odd as I can't seem to find any documentation on which cases that method should return null.

The server is Openfire, if it helps.