Please avoid using long wires for SWD programming. Because it may effect the clock speed. Use small wires as possible.
Also if you select low frequency, then it will set for low frequency , it won't be showing 4.5MHz. Please check whether the programmer settings are correct.
Thank you Anjana for your reply, my wires are not long. Where do you select "low frequency" ? What are the "correct" settings? Thank you. Jerome