Most common errors

Transaction errors: Insufficient funds, Error, Unknown

If you encounter any of the following messages during a transfer or swap — Error, An error occurred, Insufficient funds, or Unknown (UKWNAM9c) — the most common cause is that your wallet does not have enough TON or Battery charges to cover the network fee.

The required fee reserves for different transaction types are:

Transaction type	TON required	Battery charges
Send tokens	0.1 TON	~30 charges
Swap TON or tokens	0.3 TON	~90 charges
Send NFTs	0.1 TON	~10 charges
Send USDT (TRC-20)	—	150–350 charges

Your wallet balance must cover both the transfer amount and the fee reserve. Also ensure you are running the latest version of Tonkeeper — outdated versions can produce transaction errors unrelated to balance.

Emulation error

When Tonkeeper cannot emulate a transaction, you will see a notification similar to this:

Tonkeeper emulation error notification

An emulation error means Tonkeeper cannot preview the transaction details (the amount, estimated fee, and likely outcome) before you sign. In most cases, the transaction can still be submitted and confirmed on-chain successfully.

Before signing, verify all three of the following:

Your wallet has enough TON or Battery charges to cover the network fee (see the table above).
You are using the latest version of Tonkeeper.
Your device clock is accurate and synchronized — clock drift can cause transaction validation failures.

Slippage tolerance error (swap)

This error appears when the token price changes between the moment you initiate a swap and the moment it executes on-chain:

"Failed. Increase the slippage tolerance in the swap settings to avoid this error."

To fix: tap Swap, then tap the settings icon in the top left corner and increase the slippage percentage. A higher slippage tolerance allows the swap to execute even if the price moves slightly before it confirms.

Note: setting slippage tolerance too high may result in an unfavourable exchange rate. For most tokens, 1–3% is a reasonable starting point; highly volatile or low-liquidity tokens may require more.