Perhaps re-run the autofocus calibration procedure with the target that came with the laser? Or are you doing this in regular intervals anyhow? If you cleaned everything, my bet would be on focus also… Or the raw material you use slightly changed and you need to increase power a bit? All just guesswork…
The door problem that @andyd mentions is real, but I guess it is not the case here - if the door acts up, the laser will switch to power levels where it basically does not engrave or cut anything anymore… Btw.: If you suffer from the door problem, here’s a bit of help: Warning: Security issue - Enclosure door detection not checked at start/not fail safe - #3 by Hauke