Tendermint version: v0.34.0-rc6 (master)
What happened: Content-Type for RPC is not right. There's no such thing as text/json but there's application/json. More details here. Link for tendermint code: https://github.com/tendermint/tendermint/blob/master/rpc/jsonrpc/client/http_json_client.go#L175.
Have you tried the latest version: yes