If an approval transaction is not working the way you expected, there are steps you can take to troubleshoot the error.
Multiple approval requests
Certain tokens require existing approvals for the token to be revoked before a new approval can be submitted.
Approving a token that has non-standard approval without first revoking the existing approval results in being prompted to authorize the token again.
For a step-by-step guide on revoking an approval, see our article: “How to revoke a token approval”.
Once you've successfully revoked the token's approval, submit your swap again. You'll be asked to approve the token and set a spending limit once more.
This approval should be successful and allow you to complete the swap afterwards. For a step by step guide on approvals see our article, “What is an approval transaction?”.
It's important to note that any token can occasionally encounter this issue, not just those with non-standard approvals. Revoking and then re-approving any token which encounters this issue should help.
USDT and CRV are two tokens that follow this non-standard approval process.
Approval or Signature request not prompting your wallet
Signature and/or transaction requests from Uniswap not appearing in your wallet can be caused by a variety of reasons.
Incompatible Wallets:
- Smart contract wallets aren't compatible with Uniswap. If you're using one, you might not receive prompts to confirm transactions.
WalletConnect Troubleshooting:
- Disconnect and then reconnect your wallet to the Uniswap interface
- Ensure your wallet app (Uniswap Wallet, MetaMask, Ledger, etc) is updated to the latest version
- Consider using a different wallet app
Web Browser Troubleshooting:
- Clear the cookies or cache specifically for app.uniswap.org
- Try swapping on a different browser
- Complete a hard refresh of your browser if on a desktop:
- For PCs: Control + Shift + R
- For Macs: Command + Shift + R
Network Adjustments:
- Switch to a different network from the Network dropdown menu and then switch back to your original network.
Transaction Amount troubleshooting:
- If you have approved a certain amount, try transacting slightly below this. For example, if you've approved 1,000 USDC, try swapping only 995 USDC. You can check the amount you’ve approved on Etherscan.
Setting a token approval amount
Setting a token approval allows you to maintain control over your tokens and avoid unnecessary network costs. Below are explanations on the different types of approval amounts.
Exact Amount Approval: This approval type approves the exact amount you want a contract to access.
For example if you are attempting to swap 500 UNI to ETH, then the amount you’ll approve for an exact amount approval is 500 UNI.
This method is secure because it limits access to only what you've specified.
However, each transaction will require a new approval transaction. These approvals will require a network cost which may cost more over time.
Unlimited Approval: This approval type approves a contract to access an unlimited amount of tokens to reduce the number of approval transactions.
This method can be more convenient but comes with security risks. By approving a large amount, you are approving that the smart contract has unlimited access to that token in your wallet.
Make sure you trust the website you are using, the URL is correct, and the contract is legitimate before approving their contract to access an unlimited amount of your tokens.
If you need help verifying the legitimacy of a Uniswap contract, please reach out to our support team.
Balanced Approval: This approval type involves approving more than you need, but not an infinite amount.
For example: If you own 2,000 UNI tokens, and are swapping 500 UNI, the amount you’ll approve for a balanced approval is 750 UNI.
This way you don't have to approve every single transaction and you don't expose a significant portion of your assets.
Tips for Determining Approval Amounts:
- Security First: Always prioritize your asset's security. Only use unlimited approvals with trusted dapps.
- Evaluate Frequency: If you're using a dapp just once, the exact amount might be best. For frequent transactions, consider a balanced or infinite approval but stay informed about the risks.
- Revise Periodically: Periodically review and adjust your approvals using the Etherscan Token Approval Tool.
- Network Costs: Remember that every approval or revocation involves network costs. Consider this into your decision, especially if you're considering multiple small approvals.
In conclusion, the right approval amount depends on your individual need, security concerns, and the dapps trustworthiness.
Always be proactive in managing your approvals, ensuring a balance between convenience and safety.
If you are still encountering issues approving your token after completing the above steps please reach out to the Uniswap Labs support team.
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