proxmox/docs/09-troubleshooting/DAPP_CONSOLE_ERRORS_METAMASK.md

DApp Console Errors — MetaMask (ObjectMultiplex / StreamMiddleware)

Last updated: 2026-02-22

What you might see

In the browser console when using the DApp with MetaMask you may see:

• ObjectMultiplex - malformed chunk without name "ACK"
• StreamMiddleware - Unknown response id "…"
• MetaMask: Lost connection to "MetaMask RpcProvider"
• MetaMask: Disconnected from MetaMask background. Page reload required.

These messages come from MetaMask’s inpage script (inpage.js) and the extension’s internal stream protocol, not from the DApp’s application code.

Cause

• The ObjectMultiplex and StreamMiddleware messages are from the extension’s JSON-RPC stream (page ↔ MetaMask background). They can appear when:
  • The extension is updated or restarted
  • The tab is backgrounded for a long time
  • Multiple wallet extensions (e.g. MetaMask + MetaMask Flask) are installed
  • The browser or extension has a temporary glitch
• “Lost connection” / “Disconnected from MetaMask background” means the content script lost its connection to the extension’s background page (e.g. user locked MetaMask, restarted the extension, or the extension crashed).

What we did in the DApp

• We cannot fix or suppress these errors inside the DApp — they are emitted by the MetaMask extension.
• We added user-facing handling so that when the wallet disconnects unexpectedly, the DApp shows a toast:
  “Wallet disconnected. Please reconnect or reload the page.”
  This does not show when the user explicitly clicks Disconnect in the DApp.

What you can do

1. Reload the page after a “Lost connection” error, then click Connect Wallet again.
2. Use a single MetaMask build (e.g. disable MetaMask Flask if you don’t need it) to reduce stream conflicts.
3. Update MetaMask to the latest version.
4. Ignore the ObjectMultiplex/StreamMiddleware messages if the DApp still connects and works after a reload.

References

• MetaMask inpage provider: content script that injects window.ethereum and uses a multiplexed stream to the background page.
• Wagmi/viem in the DApp use this provider; when the extension drops the connection, wagmi’s useAccount() eventually reports isConnected: false, which we use to show the disconnect toast.