Solana transaction never gets picked up by the cluster

Question

For the last few weeks or so, we are having the following issue:

Some of our transactions, when sent via sendRawTransaction() never get picked up by the network (if we look up the txid in the explorer, it's never there), and yet web3js doesn't error out.

We use "@solana/web3.js": "^1.44.1"

This has started happening to us like 2-3 weeks ago:

• This issue affects some sets of transactions that all share the same instructions + amount of signers and accounts.
• It repros 100% of the time for all transactions in those sets. No matter the state of the network or how many times we retry, they never get picked up.
• We don't get any error back from web3.js, such as transaction limit hit
• They all work in devnet, but not in mainnet!

For one of these tx, I removed one instruction+signer and it started working, so I imagine there's some limit we're hitting, but I can't tell which or how to even determine the limit.

Answer 1

When network congestion is high, validators can drop transactions without any error. To fix your issue you could send more of the same transaction on some interval while you're waiting for confirmation, and while your transaction blockhash is valid. This way you'll raise a chances for your transaction to been processed by the validator.