In last, I just want to say that one should give heed to keeping account information and recovery phrases secure. Having
MetaMask multiple accounts can be helpful for organizing and managing different crypto assets in a single wallet, but it also means you should keep track of multiple sets of private keys or recovery phrases.
We hope that these solutions were able to help you with the problem of the
internal json-rpc error MetaMask. But if these fixes were not of any use then only the support team of the MetaMask will be able to help you out with the problem. Though we hope that just because of this JSON-RPC error you would not stop using the MetaMask Wallet.