Why does my multisig `approve_as_multi` extrinsic has failed with `InsufficientBalance` error?

Question

In this link you can find my multisig approve_as_multi extrinsic and see the InsufficientBalance error.

Does the balance error here refers to the sender (signatory) balance or the multisig address balance? Because the balance of my sender account has 0,5 WND and I was thinking it is enough.

How much balance do I need or how do I calculate it ?

Answer 1

In this link it is explained that the sender (one of the signatories) of the approve_as_multi tx needs to have enough balance to enact this tx.

To calculate how much balance the sender needs to enact this tx, you need to check the following :

1. The formula of calculation is described here and I quote it below :

Payment: DepositBase will be reserved if this is the first approval, plus threshold times DepositFactor. It is returned once this dispatch happens or is cancelled.

2. Then you will need to query in polkadot-js apps (connected in Westend) -> Developer -> Chain State -> the Multisig constants : depositFactor, depositBase, maxSignatories (as shown in the screenshot below)

   I already did it for you and the values are the following :

   • const multisig.depositFactor = 1,600,000,000
   • const multisig.depositBase = 1,004,400,000,000
   • const multisig.maxSignatories = 100 (but in your case is 2 Max signatories)

3. Additionally, you need to take into account the base units in Westend as found here

This results in the following formula : (1004400000000+2*1600000000)/1000000000000=1,0076 WND

In conclusion, the sender account needs at least 1,0076 WND in their balance to enact this tx.