Laser wont burn through 3mm board and letters are missing very small segments

My Mecpow 3x Pro used to burn through a 3mm pine (I think) board with no problem at all. Now after a 2 week absence, it wont burn through it at all. If I want to show letters on the board I have to slow the speed down to 200mm and 100% power just to make the letters come out somewhat decent and at that speed, some letters are skipping minuet sections. What am I missing. I cleaned the lens covering with alcohol and whipped it clean. Please help me with this. I am having to use a table saw to cut the piece out after I get done burning the letters out.
Thank you in advance. Brian

couple of things to check 1 focus. is it in focus? 2 clean your len. when was the last time you cleaned your machine

Just cleaned it after I noticed it acting up. Not sure how to focus it though

Yes, I did this and nothing changed. Still won’t cut through 3mm wood. Have to put speed to 200 and 100% power just to engrave letters that still come out missing about 5% of the letter. I don’t know what has happened. I changed the comm cable and no change. Lost ideas from here.

I focused the head correctly and cleaned the lens good but still wont penrtrate the 3mm wood. Fustrated.

Check if you are using mm/s change for mm/m
200 mm/s = 12000 mm/m = “no burn”.