On a side note, I converted my 3 HP M570dn models to M570dw (wireless) by installing a Wi-Fi adapter and cable.

Interesting that it's in there none-the-less. No motor moving or anything so I assume that command failed. Selecting that and then confirming that I want to clean the belt, does nothing. On of the Service Manual, ( ) it shows you how to get into the Secondary Service menu and the last option on my M570 is 'Clean Belt'. So check that too to make sure it can easily open and close and is doesn't have sticky residue under the flap and on the ITB. I just saw one where the foam material was quite degraded and sticky and possibly blocking the toner from exiting or perhaps not allowing the flap to open at all – which would just make the toner fill up in the Residual Toner Feed Bin and then all over the ITB. I did notice that when the excess toner bottle is installed into the machine, the little flap/door on the ITB where the excess toner comes out of has a foam-like material to probably prevent leaking. I do have a 3M toner vac so have used that to suck excess toner out of the Residual Toner Feed Bin.

I have 6 of these (3 M551dn and 3 M570dn) and frequently have the same issue.

Hp clean printhead test page