What is a rejected share and why do I get them?

A rejected share is a piece of mining work your pool receives but does not accept as valid credit. A few rejected shares can happen during normal mining, but a steady stream usually points to a connection, setup, or software problem.

What the pool is rejecting

When you mine with a pool, you work alongside other miners and share rewards under the pool’s payment rules. Your miner sends shares: results that prove your device is doing useful work.

A share is not usually a complete Monero block. It meets an easier target set by the pool so the pool can measure your contribution.

Before counting a share, the pool checks it. If the result arrives too late, repeats an earlier submission, or fails another check, the pool rejects it. That work generally earns you no credit.

This does not mean your wallet rejected a payment. Share checking happens before payouts and is separate from receiving XMR.

Why shares get rejected

The reason shown in your miner’s log—the list of status messages—is your best clue.

• Stale or expired job: Your miner worked on instructions the pool no longer accepts. This can happen when the network finds a new block or your connection delays a submission. Some pools handle stale work differently.
• Low difficulty: The share does not meet the pool’s required target. Here, “difficulty” means how hard a result must be to qualify. A miner using an outdated target or an incompatible setup can cause this.
• Invalid result: The pool checks your calculation and gets a different answer. Possible causes include faulty mining software, the wrong mining algorithm, or unstable hardware. Monero uses RandomX, its mining calculation method.
• Duplicate share: Your miner submitted the same result more than once. Reconnection problems or software bugs can trigger this.
• Unknown job or unauthorized worker: The pool cannot match your submission to active work or a valid mining session. Check your connection settings and login details.

Pools do not all use the same labels. Read the full error message rather than relying only on the rejected-share counter.

Why browser mining can make it worse

Your browser may slow down background tabs, pause a page, or lose its connection when your device sleeps. If mining resumes with old work, the pool may reject the next submissions.

An unreliable Wi-Fi connection, a busy internet connection, or a distant pool server can also delay work. Faster download speeds alone do not necessarily help; what matters more is a stable connection with little delay.

Browser mining software must also correctly handle new jobs, changing share targets, and reconnections. If it does not, changing your device settings may not solve the problem.

What you should check first

Look at both the rejection percentage and the reasons, not just the total count.

• Watch results over a meaningful period. One rejection among a handful of shares tells you little.
• Check whether rejections coincide with sleep, tab switching, or dropped connections.
• Confirm the pool address, port, and required login format.
• Update your mining software or reload the mining page.
• If results are marked invalid, undo overclocking—running hardware above its standard speed—and check temperatures.
• Compare the pool dashboard with your miner’s accepted-share count.

There is no single acceptable rejection rate for every setup. Persistent or rising rejections deserve investigation.

The bottom line

Rejected shares are work the pool cannot credit, not missing wallet payments. Use the rejection reason to guide your fix: late work suggests connection or pause issues, while invalid work points more toward software or hardware.