No MWF expert but I have used it successfully for a bit.
Could you tell us what the "not working" trait is?
Too thin, drys out, lather collapses?
Can you get the brush to load?
If you can, what happens next?
If you had not had success before this would be (relatively) easy - we would tell you practice and use more water.
But you have done this before, so we are vexed...
Keep us posted...please...