Boss2436 came with three different nozzles?Having glass engraving issue is it related

I am new to laser engraving, learning as I go, so far very happy with my boss laser 2436 except for when I am trying to engrave on glassware.

Not sure what I am doing wrong but I cant get a consistent engraving all the way around.

will skip parts totally, , have tried changing power and speed settings and this doesn't have any effect on my problem. The machine did come with three different length nozzles, so I am thinking I am using the wrong length nozzle.

Any insights into problems engraving glassware , and what the different length nozzles are for is greatly appreciated.

Love the Boss laser for the money , but documentation could use some help.

Thank you
James Deutschkron
Kreative Recognition