You need to switch to the Ethereum Network or Rootstock in your MetaMask. You are probably on a different chain?
I am on the Ethereum(ERC20) chain itself and I did try switching to other chains, but nothing rectified it. This is a major issue that needs to get rectified asap.
You can only place lay bets by using the API or any custom interface.
This is really disappointing to hear. It was far, far easier placing lay bets in Fairlay which resembled Betfair in several ways. I won't be putting in extra effort to just place some lay bets here especially when the liquidities are low everywhere.