Small leak from the connection between the keg and the hand tap?

[Omega]

I get a small leak when I connect tap line to the keg. The leak is in the connection of the ball lock disconnect and post. I thought the Ball Lock Disconnect was not working correctly, so I tried a few others, but it still leaked. Maybe the post is not working? However, it used to work fine before and does not leak when I disconnect
Thank you

 

[Buffers brewery]

Could be a bit of damage to the o-ring on the beer post?