It's important to first verify if there are any jammed or damaged nails inside your tool. If you find any, they need to be removed.
Possible cause:
Jammed or damaged nails
To safely remove a jammed nail, follow these steps:
Remove the battery from the tool.
Open the magazine and remove all the nails.
Pull up on the Tool-Free Jam Release and unhook the latch.
Lastly, check if the tip of the driving mechanism is in its initial position. If it's not, use a flat head screwdriver to push it back into place. Be sure to remove any bent nails you come across.