battery charged but not working ( blinking battery icon on Top lcd)

Hey, I have a canon 70D and 3 batteries: two batteries are original and the third one is third party. all batteries works well, except an original battery that I did not use for 2 months.

When I put the battery into my Canon Camera, the camera did not start and when I have a look at the Top LCD, it shows me a small Battery icon that is blinking.

So, I’m wondering if my battery is dead or I can do something to fix it.

Thanks!