In my experience of irrops on KLM, they can be very slow at proposing automatic alternatives, and they usually propose a next-day solution before closer-in options are proposed.

Of course, it this occurs late in the day, it's likely that you won't get a second wave of options proposed.

In any case, you should not simply accept whatever the app tells you - if you're at their hub airport go to an agent, or else ring up.