Plug Leaking 727

I first tried tightening the fitting and it was tight. I then loosened it a little to see how much fluid would come out and when I did, dried up white Teflon fell off of the plug. So I grabbed a rubber plug and shoved that into the hole as I pulled out the pipe plug. I cleaned the old Teflon off of the plug and added some Right Stuff sealant and swapped out the rubber plug with minimal leakage.
I did not see any cracks and I think the leak was caused by the hardened Teflon sealant. But I will check it in a couple of days to see if that fixed it or not.
Thanks for the replies.