web3 has been connected to Infura node, can send signed transactions but web3.eth.filter is not working(405 error)?
INFURA returns 405 for unsupported methods, which include the filter methods. At the moment we don't support creating filters, which store state in the Ethereum client, for our public infrastructure. This may change in the future.
The list of supported methods is here: https://infura.io/docs/