Miscalculated Child Pays for Payment. What will happen?

[invisiblej]

I've sent about 10 Bitcoin payments over the past year and never had issues. My most recent payment hasn't been confirmed after nearly 2 days (I was using an old version of Tails, so my Electrum didn't have the RBF option), so I decided to try Child Pays for Payment after updating to 2.8.2.

However, I miscalculated the fee. Instead of paying .0022 BTC/kb for the total size, I only paid .0022 BTC/kb for the child payment, which obviously isn't much. I tried increasing the fee to the correct amount of .00319 BTC total (my wallet has .0173 BTC remaining), but Electrum just says "Cannot bump fee: could not find suitable outputs."

If I just wait, will both transactions eventually cancel and return to my wallet? Or is there something else I should try?

Thank you for any help.

Original transaction ID: 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70
Child transaction ID: 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70

[1714798016]

1714798016

[1714798016]

1714798016

[mocacinno]

I've sent about 10 Bitcoin payments over the past year and never had issues. My most recent payment hasn't been confirmed after nearly 2 days (I was using an old version of Tails, so my Electrum didn't have the RBF option), so I decided to try Child Pays for Payment after updating to 2.8.2.

However, I miscalculated the fee. Instead of paying .0022 BTC/kb for the total size, I only paid .0022 BTC/kb for the child payment, which obviously isn't much. I tried increasing the fee to the correct amount of .00319 BTC total (my wallet has .0173 BTC remaining), but Electrum just says "Cannot bump fee: could not find suitable outputs."

If I just wait, will both transactions eventually cancel and return to my wallet? Or is there something else I should try?

Thank you for any help.

Original transaction ID: 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70
Child transaction ID: 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70

yes, if you wait long enough, most nodes on the network will eventually drop both transactions from their mempool, and you should be able to re-create the original transaction with the same inputs.

There are many other options to get your transaction into a block:
https://www.mocacinno.com/feecheck.php?txid=0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70

For example, you could use viabtc, pay a miner, double spend the inputs for the transaction into a new transaction with a higher fee, double spend the inputs you used for the CPFP but leave a higher fee,...

Since you're sending between your own wallets, i'd personally try to create a brand new transaction using all or most of the inputs you used for transaction 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70. This would cause a double spend, and once the new transaction with a higher fee makes it into a block, transaction 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70 will be using inputs that are no longer in the UTXO, thus it will be voided.
This will cause your CPFP tx to be voided to, since it relies on outputs from the previous tx.

This way, i think the end result would be a bit cleaner, plus you won't have to pay the fees  twice, plus you won't take up unneccesary space in a block.

Offcourse, waiting will work to... The tx will either be dropped from the mempool of most nodes, or some miner will decide to add you to the block he is currently working on, and with a bit of luck, the transaction(s) might actually confirm...

[invisiblej]

Thank you very much for your quick reply and showing me that Mocacinno site. Very useful!

I guess I'll just wait it out. But do you know why Electrum isn't allowing me to increase the fee on the child transaction? I have enough BTC, so why does it say "Cannot bump fee: could not find suitable outputs"?

EDIT: Just realized that I accidentally posted the same ID for both transactions.

Original: 0cf4b23dc1fab5ca38a497498947ed76de184b077618419802ed456c4e3e9d70

Child: df3eb943d0eb7990a7b484b56abcaf50cd85c646d8a676f3d731dcc9232640f6

[mocacinno]

Thank you very much for your quick reply and showing me that Mocacinno site. Very useful!

I guess I'll just wait it out. But do you know why Electrum isn't allowing me to increase the fee on the child transaction? I have enough BTC, so why does it say "Cannot bump fee: could not find suitable outputs"?

As far as i can tell, you created a tx in tails with insufficient fees, the output of the transaction went to a second wallet.
Since you were the receiver from the standpoint of the second wallet, the only thing you could do is creating a CPFP. In order to do so, the wallet would have used the output it got from the transaction generated by the tail's wallet as an input for a second transaction. The fee for the second transaction should have been sufficient to cover the first and the second transaction. However, you missed and broadcasted a CPFP transaction that didn't include a fee that was sufficient to cover both transactions.

Since you said you tried to bump the fee, i can only suppose the CPFP transaction was opt-in RBF, bumping the fee in an opt-in RBF transaction means that your wallet will use the same inputs and will generate outputs to the same addresses as the original transaction, but it will subtract more miners fees from one of your outputs.

I suppose this error message means (i could be wrong here) that looking at the original opt-in RBF transaction's inputs and outputs, it couldn't find a technical way of adding more fees when it could only use this fixed inputs and still had to generate outputs to the same addresses. Since the transaction has to use the same inputs as the original one, it doesn't matter if you wallet had enough funds, most of the inputs to your wallet's addresses weren't used in the opt-in RBF transaction, so they can not be used to bump the fee.

However, you could still manually create a transaction doing allmost the same as an RBF, but using extra inputs to cover the fee, or change the addresses that could spend the outputs, since an RBF is just a nice implementation of double spending the unconfirmed inputs... Doing this would be a little bit harder, and would require several steps and some technical knowledge tough...