sendTransacton throwing unknown error

[Sharaddition]

The wallet and other functions are working fine except the sendTransaction, and neither the error is clear enough for what to look on.

Here is my code -

if (state === HathorWallet.ERROR) {
  console.log("Oops Wallet failed to load...");
} else if (wallet.isReady()) {
  let address = "WNu8RmBqUbr2khES1PybQSE6iHrQbgnnaU";
  let value = 2;
  let token_id = '00';
  let changeAddress = null;
  const response = await wallet.sendTransaction(address, value, { token: token_id, changeAddress });
  console.log(response);
}

Error -

Uncaught (in promise) Error: Assertion failed
    at n (bn.js:6:21)
    at o.toBuffer (bn.js:529:5)
    at t.u.toBuffer.u.toDER (signature.js:169:22)
    at Object.getSignature (transaction.js:447:37)
    at Object.signTx (transaction.js:413:30)
    at Object.prepareData (transaction.js:767:26)
    at r.value (sendTransaction.js:239:43)
    at r.<anonymous> (sendTransaction.js:462:12)
    at f (runtime.js:63:40)
    at Generator._invoke (runtime.js:294:22)