Hello, guys. I have a lot of theoretical knowledge of how bitcoin and lightning network should work. Unfortunately when I tried to play with some wallets sometimes I hit some problems. Here's one of them.
I downloaded Zeus and I wanted to try its lightning functionality. I don't exactly know how how LSPs work and what wrapped invoices and stuff is, and I also wanted to test what I thought was a more standard use case of lightning network - opening channel from my end, sending sats from it and then receiving sats on the same channel (after sending). So I sent some sats onchain to Zeus. After the transaction confirmed I opened a (non announced) channel to the Olympus server. I used the conveniently placed "open channel to olympus" server, thinking that since this is their server it should play nice with the app. The channel opened successfully after some time. Then I sent some sats to my other wallet, so that the channel has some inbound liquidity. And it has. It says that I have 1200 satas inbound liquidity.
However when I tried receiving some sats it failed. First I tried using Mutiny wallet (from a fedimint... I know you guys here don't like eCash but that's currently beside the point). Since Mutiny gives extremely stupid and useless error messages I decided to try using Muun (which I also know you don't like since it makes submarine swaps). Here Muun gives a hint to enable route hints (because channel is unannounced). So I opened Zeus, found that there is a convenient setting on the invoice creation screen that enables route hints (why isn't is this on by default I don't know, since Zeus knows that the channel is unannounced). I enable route hints and create another invoice. Payment fails, with Muun saying that there is no available route.
I don't understand why no available route. There is enough balance on the remote side, there is (I suppose) inbound route to the Olympus server. So why can't I receive sats via this channel?
Mutiny lightning fees are around 1%. I wanted to test if this is because of what the lightning gateway was charging me to exit the fedimint and so I needed a real lighning channel. Now I want to understand why this channel does not behave as I thought it will.
Is this a place to ask such questions? If not is any such place on this site?
Different federations can have different gateways with different fees.
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Zeus
Are you using the embedded node? If so, the app needs to be open as the main app in order to receive payments.
What I would recommend is signing up for Zeus's LN address service. This will create an LN address(similar to the one that stacker.news provides) that creates a HODL Invoice for your node - when you send to your Zeus address, then switch back to Zeus you can go and 'collect' your payment when you come back online (by opening the app).
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Thanks for your answer. I will probably do what you tell me in a later time. But since I am experimenting I want to know why I can't receive on my current channel setup. (I am currently using bitcoin only for experimentation... I don't know anybody that will pay me in bitcoin nor where I can pay for something with bitcoin, besides paying for posting here).
I think I don't always need to keep the app on top, since the OS (Android) usually doesn't kill apps immediately. But I did attempt to deposit and withdrawal some sats from this very site. And ... deposit worked (using the channel mentioned), but withdrawal (with the app open on the foreground) didn't work with the same error (no route). Maybe Olympus server doesn't like using them like that?
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why I can't receive on my current channel setup
Is about no inbound liquidity, for sure. As I understand you open the channel from your onchain balance towards the Olympus LSP. That means you will not have the additional 100k inbound liquidity that Olympus is offering when you open the channel "on the fly", from any other LN wallet.
Please read more about LN liquidity works. I will suggest to move 50% of that channel out to another LN wallet, temporary, to make some more "space" in that new channel, then you will be able to receive just fine. Or buy an inbound channel from any other LSP. An inbound channel is an "empty" channel, it means the balance is on the peer side, not on your side, so you can receive straight away.
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Hello. I read and I think I know how lightning network liquidity works.
I think I DO have incoming liquidity because
  1. I used this channel to send currently total around 1200 sats.
  2. When I open my channel, I can see under "Channel balance" -> "Inbound" it says "1200 sats"
Keep in mind that I tried to receive 1000 sats, then 100 sats, then 1 sat. All attempts failed. I tried the same with the app open on the foreground.
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Or buy an inbound channel from any other LSP
Buying inbound is underrated. makes life loads easier. Also the guide is mint, plz read it @BallLightning
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But since I am experimenting I want to know why I can't receive on my current channel setup.
It's a Zeus thing. Your node has to be online & it does not run in the background (others do this, Zeus does not in my experience.). You've got to open it up to get it 'online' each time.
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Be careful with the LN Address service, it has (IMO) noteworthy fees. Not that it should discourage you from using them, just be aware
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absolutely be aware - should be used for larger amounts only
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