Because your transaction fee is too small, you use your Private key to sign a new transaction with a fee equal to or slightly larger than the current bitcoin fee and push the transaction through an intermediary website such as:
https://coinb.in/#broadcastYou can learn more at the above website.
This wont solve anything since the issue isn't about broadcast,
It's the actual process of creating a replacement in Bitcoin Core (
if he's the sender) or CPFP if he's the receiver.
And there's no point in using another service to broadcast it, he can use his node.
If at the start, he informed that he's also the sender and using Bitcoin Core, the process would've been as simple as:
1. "
rebroadcast", then 2. "
bumpfee" within Bitcoin Core.
If you still can't solve the problem, I have a way for you to try:
OP replied and with it, he confirmed the assumptions that he created the RBF transaction I saw early. (
he mistakenly though it was CPFP)
The issue is solved already.