Failed & Stuck Transactions

I made the wrong transaction. Can I cancel/refund a transaction?

Once a cryptocurrency transaction is confirmed and added to the blockchain, it cannot be canceled or reversed. This immutability is one of the fundamental features of blockchain technology. The only way to reverse a transaction is to ask the recipient to send the funds back if you know who they are.

What should I do if I sent funds to an exchange but forgot to indicate the memo/tag?

If you forget to specify a memo or tag when transferring cryptocurrency to an exchange, contact the exchange support team. They typically have a procedure for these cases.

Provide them with all the necessary details about your transfer, such as the transaction number, transfer amount, and any other information that can help them identify your transaction. The exchange can assist in restoring the transfer according to their policies and capabilities.

To find your transaction details, follow these steps in the app:

1. Select the token involved in the transfer from the home page.
2. Tap Explore Transaction History or Explore. This will direct you to your wallet's public address in the explorer.
3. Scroll through the list of transactions until you locate the one you need.
4. Tap on a transaction to view its details.

My transaction is stuck in processing

When you send cryptocurrency, the network fee determines your priority in the queue of pending transactions. The size of the fee accompanying the transaction affects how long it takes for the transaction to be confirmed on the network. If the fee is too low, the transaction may remain pending for a longer period of time or may not be confirmed at all.

Miners prioritize transactions with high fees. Therefore, choosing high fees results in quicker confirmation, while opting for lower fees means you can save on fees but may have to wait longer for confirmation. The current commissions for Bitcoin can be found on websites like https://mempool.space/.

Tangem provides 3 levels of commissions depending on the current network load: slow, market, and fast. You can also set your own network commission for your transaction. The commission amount offered by the application is calculated based on the network load, transaction volume, and execution priority. It's essential to ensure that the commission size is sufficient to confirm the transaction if you set the commission amount yourself.

You can find more information about the network commission in our blog post: What is a Transaction Fee in Crypto and How is it Calculated.

I received tokens/ NFTs that I did not send. How can I see them in my wallet?

If you notice tokens or NFTs in your blockchain explorer that you did not purchase, trade, or expect to receive, they are likely tokens created to generate interest in a project, or they may be scam tokens. Some blockchains allow for the programming of a smart contract to send tokens to a long list of active addresses or to addresses with certain parameters.

This does not necessarily mean that the scammers know your address or personal information. Tokens are often sent out in large numbers, similar to email spam.

It is not advisable to engage with these tokens or attempt to send or exchange them. Any value they appear to hold is likely fake and intended to entice users into the scam.

These tokens cannot harm your wallet merely by being in your wallet. However, if you do interact with them, you may inadvertently give permission to send cryptocurrency from your wallet, initiate a failed transaction with a high gas fee that benefits the scammer, or become a victim of a malicious contract in other ways.

Why do I see a transaction I did not perform in my transaction history?

We strongly recommend ignoring such transactions and not engaging with them, as they are linked to fraud.

On some blockchains, you can start a transaction from an address that isn't yours. If the transaction value is 0, you don't need to sign it with the private key of that address.

This means that when you send a transaction, you may see a similar recipient address (with similar starting and ending parts but different in the middle) in your transaction history.

The scam tries to trick you into copying a recipient address from a blockchain explorer and using it in a second transaction, but you may accidentally copy a similar, fraudulent address.

To better understand this scam and its details, check out the blog post: Why You Should Never Copy Addresses from the Blockchain Explorer.

How can I push a pending transaction through?

What is a nonce? 
A nonce is essentially a unique identifier for each transaction associated with a specific address on EVM blockchains like Ethereum, BNB Smart Chain, and Polygon. Each new transaction from this address receives the next sequential number: 0, 1, 2, and so on. 

Key Point: The blockchain only processes one transaction with a particular nonce at a time. 

Why do pending transactions block the queue? 
When a transaction gets stuck, usually due to an insufficient fee, all subsequent transactions with higher nonce numbers (e.g., +1, +2, etc.) remain "pending" and cannot proceed. The blockchain will not accept new transactions until the stuck one is resolved or replaced. 

If you've sent multiple transactions but none are being confirmed, check if any of them have a lower nonce than the others. It's the one with the smaller nonce that might be holding up the queue. 

How do I find the nonce of a pending transaction? 

1. Open the transaction in the blockchain browser. 
2. Find the More details or the Advanced section. 
3. Find the Nonce field — this is the number. 

How can I replace a pending transaction? 
To replace a pending transaction, you need to send a new one with the same nonce, but with a higher commission. 

To execute the transaction: 

1. Launch the Tangem app and sign in to your wallet. 
2. On the home screen, choose the cryptocurrency sent in the initial transaction. 
3. Tap Send. 
4. Enter the recipient's address, which might differ from the original. 
5. Specify the amount of tokens or their dollar equivalent, which could also vary. 
6. Select Custom in the Network fee option. 
7. In the following fields: 
   • Enter the nonce of the suspended transaction, retrievable from a blockchain explorer. 
   • Set the commission higher than that of the initial transaction with the same nonce. 
     We advise using the recommended fees under Market and Fast. 
8. Review all details and confirm by tapping Send. 
9. Confirm the transaction to sign it. For more details, see How to confirm actions in your wallet.

If everything is correctly set, the new transaction will replace the old one and be confirmed on the network. 

Which networks support transaction replacement? 
This feature is available on all EVM networks, including ApeChain, Arbitrum, Areon, Aurora, Avalanche C-Chain, Base, Bitrock, Blast, BNB Smart Chain, Canxium, Chiliz EVM, Cronos, Cyber, Dione, Ethereum, Ethereum Classic, Ethereum PoW, Fantom Opera, Flare, Gnosis, Hyperliquid EVM, Kava EVM, Manta Pacific, Mantle, Monad, Moonbeam, Moonriver, Optimistic Ethereum, Polygon, Polygon zkEVM, PulseChain, RSK, Shibarium, Sonic, Telos, zkSync Era.

What happens if I don't specify the nonce manually? 
If you send a new transaction without manually setting the nonce, it won't replace the suspended one. The transaction will receive the next available number and wait until the previous one is confirmed. Both transactions will incur a fee. 

I have multiple pending transactions. What should I do? 
If you have several pending transactions, start with the first one (the one with the smallest nonce) and replace it step by step until you unlock the entire queue. 

Important: When replacing the first suspended transaction (the one with the lowest nonce), the blockchain can automatically process subsequent transactions if they have a sufficient network commission. This is handy if you want to send all your transactions simultaneously, but it also carries a risk if you intend to execute only one.