Testnet fee estimation not working and causing issues?

[Jodmapht]

Hi,

I would like to do some lightning tests using testnet3 and I am unable to open a channel with a node because my testnet bitcoind is unable to estimate fees. I get a "Cannot estimate fees" error regardless of how long my node has been running for (i.e. multiple months or a few hours). Is this normal, and what is the way around this issue that people use?

Thanks!

[BitMaxz]

Did you check your node if it's fully sync?
Better check the node first by using "bitcoin-cli getblockchaininfo" and compare the block with the current block height of 4,075,142

If the block info is below that height, it is not fully synced yet, and you need to wait for your node to be fully synced.

[Jodmapht]

Did you check your node if it's fully sync?
Better check the node first by using "bitcoin-cli getblockchaininfo" and compare the block with the current block height of 4,075,142

If the block info is below that height, it is not fully synced yet, and you need to wait for your node to be fully synced.

Yes it is fully synced. Before I rebooted it a couple of hours ago it had been running for months. And the blockheight matches mempool.space/testnet

[BitMaxz]

Yes it is fully synced. Before I rebooted it a couple of hours ago it had been running for months. And the blockheight matches mempool.space/testnet

Are you running a prune node? I suggest disable it if it is set to prune.

Are you able to send tBTC on-chain? I mean normally send testnet coins, not by opening channels. Test it first and let's see if this is only by opening the channel or even on-chain doesn't work.

What is your current node system specs? Are you in Ubuntu?

Can you try to edit the bitcoin.conf and add this "maxmempool=500" without qoutes or change it to 1000 then test make sure to restart bitcoind.
If you still having issue try adding this on the Bitcoin.conf file "mempoolexpiry=72" then restart it again and test.

[Jodmapht]

Yes it is fully synced. Before I rebooted it a couple of hours ago it had been running for months. And the blockheight matches mempool.space/testnet

Are you running a prune node? I suggest disable it if it is set to prune.

Are you able to send tBTC on-chain? I mean normally send testnet coins, not by opening channels. Test it first and let's see if this is only by opening the channel or even on-chain doesn't work.

What is your current node system specs? Are you in Ubuntu?

Can you try to edit the bitcoin.conf and add this "maxmempool=500" without qoutes or change it to 1000 then test make sure to restart bitcoind.
If you still having issue try adding this on the Bitcoin.conf file "mempoolexpiry=72" then restart it again and test.

No it is not a pruned node:


 ./bin/bitcoin-cli -testnet getblockchaininfo
{
  "chain": "test",
  "blocks": 4075162,
  "headers": 4075162,
  "bestblockhash": "000000000ff380e4ddabeaef62b63a23a29b57fe0c93257a2aaf5a6420c66ffd",
  "difficulty": 1,
  "time": 1742866878,
  "mediantime": 1742865677,
  "verificationprogress": 1,
  "initialblockdownload": false,
  "chainwork": "0000000000000000000000000000000000000000000016426f159b1301805f97",
  "size_on_disk": 189685877847,
  "pruned": false,
  "warnings": "Unknown new rules activated (versionbit 28)"
}


I am using FreeBSD on arm64. I have bitcoind running in another jail with mainnet and I don't have any issue. I had maxmempool set to 300, I just increased it to 1000 and set mempoolexpiry to 72:


2025-03-24T23:56:36Z * Using 37.2 MiB for transaction index database
2025-03-24T23:56:36Z * Using 32.6 MiB for basic block filter index database
2025-03-24T23:56:36Z * Using 8.0 MiB for chain state database
2025-03-24T23:56:36Z * Using 220.2 MiB for in-memory UTXO set (plus up to 953.7 MiB of unused mempool space)



./bin/bitcoin-cli -testnet estimatesmartfee 1 economical
{
  "errors": [
    "Insufficient data or no feerate found"
  ],
  "blocks": 2
}

[Jodmapht]

Are you able to send tBTC on-chain? I mean normally send testnet coins, not by opening channels. Test it first and let's see if this is only by opening the channel or even on-chain doesn't work.

Sending a tx works just fine...

[BitMaxz]

Is not fully synced yet look at the blocks under "getblockchaininfo" and compared it to the current block height from https://mempool.space/testnet

The current block is 4075204 but yours is currently 4075162

I don't see any other reasons, but this current block height in your node seems to be the issue the node should be fully synced.

The weird part is "verificationprogress": 1 it indicates a fully synced.

If the normal transaction works just fine would you mind to add more info if what lightning software or wallet you use to open a channel? If the issue only comes up when opening a channel, then maybe the issue is only in your lightning software or wallet.

[Jodmapht]

Is not fully synced yet look at the blocks under "getblockchaininfo" and compared it to the current block height from https://mempool.space/testnet

The current block is 4075204 but yours is currently 4075162

I don't see any other reasons, but this current block height in your node seems to be the issue the node should be fully synced.

The weird part is "verificationprogress": 1 it indicates a fully synced.

If the normal transaction works just fine would you mind to add more info if what lightning software or wallet you use to open a channel? If the issue only comes up when opening a channel, then maybe the issue is only in your lightning software or wallet.

Again getblockchaininfo returns me the same height as mempool.space, and estimatesmartfee returns "Insufficient data or no feerate found". I am using CLN to open a channel

[Jodmapht]

Is not fully synced yet look at the blocks under "getblockchaininfo" and compared it to the current block height from https://mempool.space/testnet

The current block is 4075204 but yours is currently 4075162

I don't see any other reasons, but this current block height in your node seems to be the issue the node should be fully synced.

The weird part is "verificationprogress": 1 it indicates a fully synced.

If the normal transaction works just fine would you mind to add more info if what lightning software or wallet you use to open a channel? If the issue only comes up when opening a channel, then maybe the issue is only in your lightning software or wallet.

Again getblockchaininfo returns me the same height as mempool.space, and estimatesmartfee returns "Insufficient data or no feerate found". I am using CLN to open a channel

Hmm, estimatesmartfee just started working without me changing anything...

Changed the settings back to the original ones I had, restarted bitcoind, and fee estimation still works. Not sure what happened?

[ABCbits]

Again getblockchaininfo returns me the same height as mempool.space, and estimatesmartfee returns "Insufficient data or no feerate found". I am using CLN to open a channel

Hmm, estimatesmartfee just started working without me changing anything...

Changed the settings back to the original ones I had, restarted bitcoind, and fee estimation still works. Not sure what happened?

I believe this answer on Bitcoin StackExchange mostly answer your question.

The fee estimator tries to estimate the fee the balances between cost and time to be included in a block. It does this by looking at the fee rates of transactions that it receives in its mempool and seeing how long it takes for transactions at a given fee rate to be included into a block. It becomes more accurate as it sees more transactions and more blocks because it has had more data to analyze.

Just wait. Leave the nodes online. The estimators require data and the only way to do that is to wait. They become more accurate over time.

[nc50lc]

Hmm, estimatesmartfee just started working without me changing anything...

Not surprising since it's been a while since you've experienced the issue, it's just given enough time to work.

If that happened again and you're in a hurry, you can try to set a "fallbackfee" so its value will be set instead if the estimate isn't available yet.
Set it to your bitcoin.conf file like: fallbackfee=0.0001
The value's unit is in "BTC/kB".

[Jodmapht]

Again getblockchaininfo returns me the same height as mempool.space, and estimatesmartfee returns "Insufficient data or no feerate found". I am using CLN to open a channel

Hmm, estimatesmartfee just started working without me changing anything...

Changed the settings back to the original ones I had, restarted bitcoind, and fee estimation still works. Not sure what happened?

I believe this answer on Bitcoin StackExchange mostly answer your question.

The fee estimator tries to estimate the fee the balances between cost and time to be included in a block. It does this by looking at the fee rates of transactions that it receives in its mempool and seeing how long it takes for transactions at a given fee rate to be included into a block. It becomes more accurate as it sees more transactions and more blocks because it has had more data to analyze.

Just wait. Leave the nodes online. The estimators require data and the only way to do that is to wait. They become more accurate over time.

Ok, it is strange that there was no fee estimation after bitcoind had been running for months, then no fee estimate for 24 hours after restarting, then now it works regardless of if I restart it or not. Was it due to a lack of txs in the testnet mempool?

[Jodmapht]

Hmm, estimatesmartfee just started working without me changing anything...

Not surprising since it's been a while since you've experienced the issue, it's just given enough time to work.

If that happened again and you're in a hurry, you can try to set a "fallbackfee" so its value will be set instead if the estimate isn't available yet.
Set it to your bitcoin.conf file like: fallbackfee=0.0001
The value's unit is in "BTC/kB".

Ok thanks I will definitely add this to my configuration file!