A password (which is part of the "userinfo" nonterminal) may not contain unencoded "?":s anyway. You have to use %3f.
userinfo = *( unreserved / pct-encoded / sub-delims / ":" ) unreserved = ALPHA / DIGIT / "-" / "." / "_" / "~" pct-encoded = "%" HEXDIG HEXDIG sub-delims = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="