Loop out failed but "prepay" fund taken

Support and Troubleshooting
1

Dear community,

I am learning about how to set up and operate an Umbrel node.
I successfully installed (and subsequently upgraded to latest version) Umbrel on a Raspberry Pi with an HDD connected directly into my router via Ethernet. The sync took a week but everything went well.

I opened my first two channels with ACINQ and Walletofsatoshi and obtained inbound capacity with a couple of loop outs that worked just fine (one took 4h and the other 12+). In both of them I sent capacities of 250-310K sats and an amount of exactly 30.000 sats was sent automatically from my wallet in the concept of “prepay”, after which you could see a transaction that looked something like “swap-script: 002923…”. All good until this point since at the end of the process my net balance would end up being the same except for the very small fees for the loop out.

However, I just opened a new channel with 1ML.com node ALPHA and tried doing the same, looping out some capacity. In this case, the loop failed (I get an On-chain Timeout error on Lightning Terminal) and, more importantly, the amount of 30.000 sats was sent from my account with the concept of “Prepay” but no “swap-script” transaction happened and now the balance of my overall node is 30.000 sats lower than I would expect.

Could you please help me with this?

Thanks in advance!

2

The prepay is a reserve fund for fees of closing the channel.
Loop out should not be done, at least you are a merchant that accept BTC through LN and need more inbound liquidity.
Also channels of less than 500k sats are useless, or at least are used only for tiny micropayments.
For a 200k sats channel you will have at least 20k locked in commit_fee and also will not forward too many txs until you will not det specific fees and HTLC for that channel.
If you do not know how LN is wotking, you better start reading and watching tutorials.
I put together here a long list of sources, that every noob should consult it.
http://community.umbrel.com/t/important-links-to-learn-more-about-bitcoin-lightning-network/3556/2

3

Thanks for the response and the link with info. I was midway through browsing all of that. Why do you not recommend doing Loop out? In the tutorial video in the link it is stated as one of the main ways to get inbound liquidity and therefore balanced channels. What’s the reason behind not recommending loop-outs?

thanks again!

4

The same thing happened to me. I initiated a loop out on RTL, was charged the prepayment of 30K. The loop out failed, but the prepayment was not reversed.