How to troubleshoot failed lightning network electrum

[ethereal1m]

Hi,
I was able to send 6 mbtc but failed to receive lightning network payment. These were what I did:
1. I opened a channel.
2. I reverse swaped it using submarine swab by clicking max button. It says it should increase the receiving capacity. The electrum history says reverse swap 0.53 mbtc.
3. I failed to receive multiple amount. The capacity was around 6.5 mbtc (according to channel detail it could receive that amount), but failed to received 4 mbtc.
4. Try to increase receiving capacity by doing  submarine swab again. But on the electrum history tab it says forward swab 6.4 mbtc and channel detail said it can receive 0.179 mbct.
5. I thought I increased tx capacity by accident, so I try to swap it again but got "payment failed no path found" error.

Questions:
1. Why did I fail to receive 4 mbtc even though the channel said can receive 6 mbtc?
2. How to troubleshoot when failed to receive? How can check network nodes from the tx side to rx side?
3. How to fix "no path found error"?

regards

[1715027260]

1715027260

[1715027260]

1715027260

[jackg]

You might have to close your channel and open up another one if you don't control the other end or know who does.

I'd suggest opening a few channels at once in order to avoid issues like this and to also support decentralisation a bit more.

For a large amount of your capacity (size of transaction you're likely to send or receive) I'd recommend opening a channel with acinq: https://acinq.co/node

If you're normally a ghost/guest on this forum and recognise users you might want to take a look at my thread on users here that are running lightning network nodes too: https://bitcointalk.org/index.php?topic=5266907.msg54940969#msg54940969

[nc50lc]

4. Try to increase receiving capacity by doing  submarine swab again. But on the electrum history tab it says forward swab 6.4 mbtc and channel detail said it can receive 0.179 mbct.

This will happen if you click the "lightning icon" in submarine swap window, that'll swap the BTC and Lightning icons switching it to "forward swap".
Forward swap will decrease your inbound capacity instead.
Since it worked and decreased your inbound capacity, that confirmed that you can receive LN funds before the forward swap transactions.

2. How to fix "no path found error"?

Mostly it's a channel routing issue (the solution is the post above); but since you've done a max forward swap, it's your inbound capacity.

1. Why did I fail to receive 4 mbtc even though the channel said can receive 6 mbtc?

It could be a channel routing problem of the one who's paying you
or your channel(s)' status aren't open yet when you tried to receive, can also be a bad connection.

Based on personal experience, I've been experiencing those "no path found" error at random chance specially if the wallet has just opened.

[ethereal1m]

more questions:
1. How to minimize probability getting "no path found" error when try to receive btc, besides opening up more channels? Is there a guide to show how
which channel is better than the others. Or is there a node network map to see rx path?
 
2. If I can receive without problem from a channel, is it possible if it gets "no path found" in the future?


regards

[nc50lc]

1. How to minimize probability getting "no path found" error when try to receive btc, besides opening up more channels? Is there a guide to show how
which channel is better than the others. Or is there a node network map to see rx path?

There's a famous "Lightning Network Search and Analysis Engine" (as it calls itself) that you can use to check if a lightning node has many channels and capacity.
Also their number of connections, usually those at the top are reliable enough.
Here's the link: https://1ml.com/ |  Top channel count: https://1ml.com/node?order=channelcount
 

2. If I can receive without problem from a channel, is it possible if it gets "no path found" in the future?

There's always a chance, since it also depends on the on the remote node's status and the payer's channels, not just yours.

[Rath_]

There's always a chance, since it also depends on the on the remote node's status and the payer's channels, not just yours.

Also, if the payment needs to be routed through other nodes, they need to have enough liquidity and match the payer's fee policy. If the payer's wallet supports multi-part payments then there is a higher chance of transaction being routed successfully.