Having no luck with lightning payments

I've been trying to send lightning payments to myself using different apps, even tested with my own node, but nothing's working. Phoenix won’t stop going offline when I switch apps, like with Breez. I turned off Tor, I'm not in power-saving mode, and didn’t close the app, but I keep coming back to it saying it's connecting. When I try sending from Phoenix to Breez, it says the recipient is offline. And when I send from Breez to Phoenix, it always says no route available. Sending from Phoenix to my node through Zeus gives me a message about insufficient fees. When I check the technical details, it looks like it's trying to pay with no fee at all for some strange reason. Then I gave Electrum a shot. Just to clarify, I funded the wallet on-chain beforehand, all outgoing payments were less than my capacity, and the recipient had enough inbound liquidity for the payments. So, on Electrum, I set up an Electrum trampoline channel to a trampoline node. I tried paying a lightning invoice from Phoenix while keeping both wallets open, but it failed every time. I can't recall the exact wording, but I think it was saying something like channel close failure or channel failure repeatedly when I checked the details. I even turned off trampoline routing, fully synced the graph, and tried again. It would show pending (1), (2) a bunch of times, take forever, and ultimately fail with the same issues, with some fee insufficient errors mixed in for a few HTLCs. Any advice would be super appreciated.

It means your device is restricting its background usage. If you are using Android follow this to enable background running. App management -  Phoenix wallet - App battery usage - Select unrestricted from the options Now your connecting while switching between apps should be resolved.

I had this on already to allow background usage and it isn't resolved. Also when receiving from electrum (from computer) I kept phoenix open in the foreground

Well OP there actually seem to be a ton of issues you are facing here from probably network related to maybe software related too. One thing is to try troubleshooting these issues. You should try checking a few things like node connectivity, verifying channel liquidity, and I think  inspecting fee calculations too since there is a chance that could be the problem. From my experience sometimes Restarting the apps and nodes, then attempting the payments again, might also help but my best guess is you have probably tried it out but to no avail. I'm not very much familiar with the lightning network and this problem seem a little new to me.

My immediate question is if the receiving channel actually has sufficient receiving capacity for your attempted payment(s). You didn't mention anything about this important detail. Yes, I'm aware that Phoenix wallet usually privides some decent percentage of receiving capacity when you open a channel. Providing enough fee for routing is another necessity for a successful payment, obviously. If I didn't misunderstand you, your tries weren't only with Phoenix wallet as receiver. Successful routing of payments can be a frustrating issue and heavily depends on to which other nodes your Lightning node has open channels. Are those nodes well connected? The choice of your channel partners can sometimes be some sort of art.

Yes I think I have cracked it. Whilst the channel that was already opened on phoenix had an inbound capacity of more than what I was trying to send, I had less than 10k sats in phoenix so it wouldnt open up new channels. I added more onchain to phoenix and tried sending from electrum and it worked instantly, then I sent back to electrum and that was also instant. Thanks.

If there was enough inbound capacity the phoenix wallet won't be requiring the channel creation fee again because it's one time thing so the channel didn't have enough inbound capacity to receive the funds so it required a new channel and due to the lack of funds the channel wasn't created and that resulted into the failure of your payment from electrum to phoenix.