First check that you have a fully charged battery - a fully charged battery maximises runtime and also power, and minimises the chance of your mower cutting out in use.
The next thing to check for is the condition of your lawn - for best performance, it's recommended to mow your lawn regularly and to mow dry grass.
Always remove obstructions such as sticks and gumnuts from your lawn before mowing as these can cause your mower to cut-out.
Mow on a higher setting before moving to a lower one if your grass is on the longer side.
If you've had your mower for a while, consider replacing the blades as new, sharp blade reduces the amount of strain placed on your mowers motor and can help avoid cut-outs.