Our app deploy Multisigs on behalf of the users and recently we did migrated to Base. What is happening is that Multisigs created using Safe Proxy Factory v1.3 + SafeL2 v1.4 is marked as Unsupported by the Safe App. And when users try to send transaction inside our app that uses Safe Protocol Kit, it returns:

Error trying to execute transaction: Contract-transaction-
hash=0x33d7b22790fd17f... does not match provided contract-tx-hash=0x9caf29bb1f0d6f6519...

Users are really pissed off and we have no idea how to solve this. These are some of the contracts affected.



The users are also unable to move any fund or transfer anything cause the Safe App itself doesn't recognize its own contracts deployed.

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1 Answer 1


What do you mean by "Multisigs created using Safe Proxy Factory v1.3 + SafeL2 v1.4"? Did you try with both?

The "official" SafeProxyFactory v1.4.1 address for Base is 0x4e1DCf7AD4e460CfD30791CCC4F9c8a4f820ec67; v1.3.0 of the same contract is 0xC22834581EbC8527d974F8a1c97E1bEA4EF910BC. Using any other addresses used to deploy safes on this network will result in the UI considering these as unsupported. Can you make sure these are the right contracts you are using?

Thanks in advance; Best, Louis

  • Yes, we used the Proxy Factory v1.3 (0xC22834581EbC8527d974F8a1c97E1bEA4EF910BC)from Base and when you call function createProxy, you need to specify a singleton(source-code for safe) to clone. In our case we are using SafeL2 v1.4.1 official deployed on base according to the deployments repo: github.com/safe-global/safe-deployments/blob/main/src/assets/… But all Multisigs created using v1.4 is not supported by the Safe SDK and Safe App UI. Apr 5 at 13:32
  • You should try deploying them using the same version between singleton and proxy factory. So in this case Factory v1.4.1 + SafeL2 v.1.4.1 too. Could you try this and confirm this solved the problem? Thanks 🙏 Louis Apr 15 at 14:20
  • Yes, it is working. It's been a while since the warning do not appear anymore on Base without any change on our side. We can't use the Proxy Factory v1.4 because it doesn't support CreateProxy function (without nonce) that we use on our code. Unfortunatelly the warning still appear on Base Sepolia, but it doesn't prevent user from use the Safe App. Apr 16 at 16:59

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