SWIX Feature failed to sign message after connect wallet

[morphiezy]

Hi, I’m encountering an issue with the SIWX feature. After the user successfully connects their wallet, the app immediately triggers the “Sign message” request — but the signing process fails and shows an error (screenshot attached).

The modal displays “Error signing message”, and the signature request doesn’t go through.
I’m not sure whether this is caused by my implementation or a potential issue in the library.

Questions:

1. Is there anything specific that needs to be configured for SIWX signing to work properly after wallet connection?
2. Are there known cases where the signature fails due to domain, nonce, or chain mismatch?

Any help or guidance would be appreciated. Thank you!

EIP155Verifier.ts

import { verifyMessage } from "viem";

import { SIWXVerifier } from "./SIWXVerifier";
import type { SIWXSession } from "@reown/appkit/react";

export class EIP155Verifier extends SIWXVerifier {
  public readonly chainNamespace = "eip155";

  public async verify(session: SIWXSession): Promise<boolean> {
    try {
      return await verifyMessage({
        message: session.message.toString(),
        signature: session.signature as `0x${string}`,
        address: session.data.accountAddress as `0x${string}`,
      });
    } catch {
      return false;
    }
  }
}

SIWXVerifier.ts

import { SIWXSession } from "@reown/appkit";

export abstract class SIWXVerifier {
  public abstract readonly chainNamespace: "eip155";

  public shouldVerify(session: SIWXSession): boolean {
    return session.data.chainId.startsWith(this.chainNamespace);
  }

  abstract verify(session: SIWXSession): Promise<boolean>;
}

export const wagmiAdapter = new WagmiAdapter({
  storage: createStorage({
    storage: cookieStorage,
  }),
  ssr: true,
  projectId,
  networks,
  transports: {
    56: http( ),
  },
});

const modal = createAppKit({
  adapters: [wagmiAdapter],
  projectId,
  networks: [bsc],
  defaultNetwork: bsc,
  metadata: metadata,
  siwx: new DefaultSIWX({
    verifiers: [new EIP155Verifier()],
  }),
});