Getting Error when calling method on ethereum smart contract (abi: unmarshalling empty output)

Question

I am using Go to interact with an ethereum smart contract hosted on the rinkby test network and get the following error when executing a method on the contract: "abi: unmarshalling empty output"

Do you have any idea what could be causing this?

This is my code for instantiating the contract and calling the method.Creating the contract does not return any errors. I've used abigen to generate the go-binding for the rpc calls.

conn, err := ethclient.Dial(gethPath)
if err != nil {
    log.Fatalf("Failed to connect to the Ethereum client: %v", err)
    return false
}

contract, err := NewTestContract(common.HexToAddress(contractAddress), conn)
if err != nil {
    log.Fatalf("Failed to instantiate contract: %v", err)
    return false
}
contract.someExistingMethod();