WETH on Mumbai testnet

I am trying to get some WETH on mumbai - so I tried to call depositEther on the deposit contract on Goerli (0x20339c5Ea91D680E681B9374Fc0a558D5b96a026) - but the call fails. Also It seems all calls to this contract fail - the only successful one is the contract creation transaction. What am I missing here?