Fix MetaMask Error -32603 Internal JSON-RPC Error (2025)

Updated: 11/29/2025

You connect your wallet to a dApp, click confirm on a swap or NFT mint, and instead of a smooth transaction you get a red banner with Error -32603 Internal JSON-RPC error. The transaction never hits the block explorer, yet your wallet balance looks unchanged and confusing. This generic error usually means something in your transaction parameters or RPC endpoint is invalid, such as gas settings, nonce, or network configuration, and it will keep failing until those details are corrected.

Table of Contents

Method 1: Increase Gas Limit And Clean Up Transaction Data

On DEX interfaces and NFT mints, make sure you are not sending token amounts with more decimals than the token supports or using slippage values that are effectively zero. Invalid amounts or routing parameters can cause the backend to reject the call before it reaches the chain, which MetaMask surfaces as an internal JSON RPC error.

Method 2: Change RPC Endpoint Or Network And Reset Account

Install MetaMask on a second browser or device, import your wallet using your seed phrase only if you are in a secure environment, and connect to the same dApp. If the transaction works there with the same parameters, your original browser profile or extension environment is likely corrupt and may need a full reinstall.

Warning: Never type your seed phrase on shared or untrusted devices, and only use the official MetaMask extension or app from verified stores.

Method 3: Fix Nonce Conflicts And Stuck Pending Transactions

When preparing a new transaction, click Advanced options and manually enter the nonce that matches what the block explorer shows as your next available sequence number. This approach ensures that MetaMask and the network agree on the ordering, preventing internal JSON RPC errors caused by out of order or duplicate nonces.