can't sign with string message.

[soring323]

Sign object. EndorsementSign: [ { name: "signer", type: "address" }, { name: "modelId", type: "uint256" }, { name: "message", type: "string" },

Solidity Struct struct EndorsementSign { address signer; uint256 modelId; string message; }

this is my structure. if I remove last message(string), sign is working well, but if I add last item, can't recover correct signer value in solidity smart contract.