Barrier error during initiating HRMP channel with Rockmine on Rococo

Question

I want to open HRMP channel with Rockmine on rococo. But I got the Barrier error and can't understand what is wrong with my request.

This is my encoded call data 0x29000101000210000400000000070010a5d4e81300000000070010a5d4e800060003005ed0b2381700e8030000e8030000009001000d010004000100a10f

There is no additional events that can help me to figure out what exactly wrong. Does anybody has any suggestion?

Answer 1

First, this is because you're using a non-root account to send the XCM of HRMP request. You should use sudo or governance to do this. If you use a non-root account to call polkadotXcm.send, it will add the DescendOrigin instruction as the first instruction into your messsage, and then blocked by rococo AllowTopLevelPaidExecutionFrom barrier.

Make sure your sovereign account in the relaychain has sufficient balance to withdraw, otherwise it will FailedToTransactAsset

Then, there are several improvements you need to pay attention to, although they're not releated to barrier:

1. You can add a RefundSurplus instruction between Transact and DepositAsset, it can refund your surplus weight for transact.
2. The beneficiary of DepositAsset should be your sovereign account on rococo, your paraId is 2124, so it should be {0, X1(Parachain(2124))}, rather than Parachain(1000). It will put unspent tokens into your sovereign account on rococo.

Answer 2

Great tutorial for opening channel with Common good parachain.

link