First, I'm not a Andis Tech.
* Check your warranty and call for service.
*** Following is for information only ***
* Normally I would suggest cleaning and tightening the 2 blade holder screws as in a normal "Human" hair clipper. But I noticed this pet clipper uses a snap on blade (or a combo blade as shone in "Blade Maint" video. Looks like it's mostly cleaning though I have seen other vids with clippers going dull during pet "rescues" having to trim matted hair. One lady used 2 blades and ending up using a 3d blade. It could be just that; really thick dirty hair. Dirt and grime is a collection of stone dust and oils after all.
* Demo; https://www.youtube.com/watch?v=Aun5QDCtGgc
* Blade Maint; https://www.youtube.com/watch?v=v-rS_YQ-ro0
* Basic Repair; https://www.youtube.com/watch?v=CRGEQHhfCIc
* Repair (detailed); https://www.youtube.com/watch?v=pbDLhMugSgg