White spots on prints M254dw

[FransHvP]

I use a brand new M254dw (few weeks old) with original HP tonercartridges.
From the first day on I have to get rid of one thirth of all my prints because of 'white spots'.
But two third of the printed pages are okay, strangely.

It makes no difference whatever paper I use (Canon Black, Yellow or Red), nore which PC I use to print with (Windows 10 or Mac Ojave, iOS et cetera).

Must be something within the printer itself, I suppose,
Hope not.
Does anyone recognize this problem and/or can explain it or have a solution?
Look at the enclosed print copies.

Thanks in advance & kind regards,
Frans Hoynck
The Hague (Den Haag), Netherlands

[Valsimot]

If you have more than one white spot on the one sheet of paper than measure distance between 2 white sports in mm and compare your measured result from a table:

If it's only one mark repeating once on a page but in a different position it's probably some dirt, piece of leftover label or even damaged transfer belt.

[Repairatrooper]

First poster has likely steered you in the right direction. Open the front door, remove the cartridges and use a flashlight to look at the grey mylar belt that runs underneath the cartridges, you will likely see something stuck to the belt or the belt is damaged. You may be able to remove it but if it was something like a lablel, the left over adhesive is likely to cause further print defects even if you remove the label.