Engine coolant leak under front of car

So, I recently flushed my engine coolant after losing some while changing my intake manifold since it came out from the tubes on the throttle body. Needless to say it was not leaking when it was low. I uncapped my coolant and twisted off the plug to release the old coolant. I flushed it out with water and let it drain and then put the plug back in. I started filling it up with coolant and it was leaking heavily from the front. There should be no leaks on any hoses. When I looked under it was coming from a hole. I could plug it up with my index finger. It felt like there was a bolt or plug there that should have been there but I looked on the floor and nothing. My coolant it leaking with in less than 20 minutes. I can’t figure out what’s going on.