In many cases, most FlightXML methods will try to silently try to normalize identifiers into ICAO, but this behavior should not generally be relied upon since there are known limitations with being able to do it for all possible idents. In particular, IATA airline identifiers that include digits will not be normalized, such as JetBlue (IATA "B6") because an ident such as "B6123" could be referring either to JetBlue 123 or an aircraft registration in China.
Technically speaking, the documentation for SetAlert
does not specifically say that IATA codes are permissible, although it is true that it will make a best effort at normalizing idents to ICAO when possible.
However, your "grantu" account has "position-only flights" enabled, while your "hbaghdas" does not have this capability enabled. When you enable that, many changes to flight visibility and ident normalization occurs, including the best-effort normalizatino of IATA idents to ICAO. If you need to have "position-only flights" enabled, then you will need to do ICAO ident normalization yourself before invoking SetAlert or other FlightXML methods.