[Bug]: The contract function "approve" reverted with the following reason: Internal JSON-RPC error

[kenorb]

Describe the bug

I'm trying to do Swap on Base, but after Approving transaction on extension it immediately fails with the following error:

The contract function "approve" reverted with the following reason: Internal JSON-RPC error.

Expected behavior

Normally it doesn't happen, but this time it happens all the time.

Screenshots/Recordings

No response

Steps to reproduce

1. https://aerodrome.finance/swap?from=0x940181a94a35a4569e4529a3cdfb74e38fd98631&to=0x833589fcd6edb6e08f4c7c32d4f71b54bda02913
2. Allow AERO.
3. MM Popup: Next, Approve.
4. Site reports: Waiting for pending actions...
   Nothing else happens for a long time.

Error: Internal JSON-RPC error, code: -32601.

Error messages or log output

More details:
app.Bsvj5173.js:6 ContractFunctionExecutionError: The contract function "approve" reverted with the following reason:
Internal JSON-RPC error.
Contract Call:
address:   0x940181a94a35a4569e4529a3cdfb74e38fd98631
function:  approve(address spender, uint256 amount)
args:             (0x6a000f20005980200259b80c5102003040001068, 294283400574972427228)
sender:    0x...
Docs: https://viem.sh/docs/contract/writeContract
code: -32603
message: "Internal JSON-RPC error."

Detection stage

In production (default)

Version

12.5.0

Build type

None

Browser

Chrome

Operating system

Linux

Hardware wallet

No response

Additional context

• This happens on most of Base swaps (Aerodrome, VFat).
• My RPC is correct.
• I don't have any visible Pending transactions in Activity.
• When I had Pending transactions, Transaction ID and Link to explorer were greyed out.
• Before I had few stuck transactions (not even visible in explorer), but I did: 'Clear activity tab data' in Advanced, then they disappeared.
• Reloading extension doesn't help.
• I've tested by sending 0 ETH to my own address with 5 GWEI and it worked without issue (transfer, but still not the swap).
• However I'm not able to do swap in any way on any website.
• The same issue was happening like for over an hour.

Severity

No response

[kenorb]

Someone suggested me a cheat code to send multiple times 0 ETH with 5 GWEI to my own address, I did that like 5 times, and my swap got unblocked at the end. But I believe it's a still the issue with MetaMask, because this isn't the first time it happened for me.