How to troubleshoot "Share Rejected" errors? (Mining Debug)

Understanding Share Rejection Mechanics

1. A rejected share occurs when a mining pool discards a proof-of-work submission due to invalid cryptographic parameters.

2. The rejection is not caused by network latency alone but by structural inconsistencies in the block header hash, nonce, or timestamp alignment.

3. Every rejected share carries an error code embedded in the pool’s response—such as REJECT_STALE, REJECT_INVALID, or REJECT_DUPLICATE.

4. GPU and ASIC firmware versions directly influence how timestamps and job IDs are parsed before submission; mismatched versions frequently trigger silent rejections.

5. Pool-side validation logic may enforce strict rules on extranonce2 length, coinbase script formatting, or compact difficulty encoding—deviations result in immediate discard.

Network-Level Validation Failures

1. Misconfigured NTP synchronization causes miner clocks to drift beyond the pool’s allowable ±30-second window, generating REJECT_STALE responses.

2. DNS resolution failures during stratum reconnects lead to stale job assignments, where the miner submits work based on outdated block templates.

3. Transparent HTTP proxies or enterprise firewalls may strip or alter X-Stratum headers, corrupting job ID integrity before reaching the pool backend.

4. IPv6-only miners connecting to IPv4-only pools often experience silent packet truncation, resulting in malformed JSON-RPC payloads that fail schema validation.

5. Load balancers without stratum-aware session persistence route successive submissions across different backend workers, breaking stateful job continuity.

Firmware and Driver Inconsistencies

1. NVIDIA driver version 535.129.03 introduces a nonce overflow bug in ethash kernels under high DAG epoch transitions, producing hashes with incorrect endianness.

2. HiveOS image v7.3.2 contains a hardcoded stratum protocol version override that conflicts with modern pool implementations requiring protocol version 2.1.0+.

3. Bitmain Antminer S19j Pro firmware v1.2.8 fails to serialize compact difficulty fields correctly when target bits exceed 0x1d00ffff, causing consistent REJECT_INVALID returns.

4. AMD ROCm 5.7 stack misaligns memory buffers during blake2b hashing on RDNA3 GPUs, injecting null bytes into the final 32-byte digest submitted to the pool.

5. Custom overclock profiles applied via MSI Afterburner may interfere with PCIe register timing, leading to intermittent hash corruption undetectable by internal hardware watchdogs.

Pool Configuration Mismatches

1. Using a BTC pool address with a BCH fork client results in valid SHA-256d computation but invalid merkle root construction due to differing sighash serialization rules.

2. Specifying “--coinbase-addr” in GMiner while mining on a pool enforcing strict coinbase script whitelisting leads to automatic rejection without explicit error feedback.

3. Enabling “--enable-stale” in T-Rex without corresponding pool-side stale share acceptance policy causes all post-fork submissions to be discarded silently.

4. Setting “--max-temp=75” on a dual-mining rig running ETH+ALGO simultaneously creates thermal throttling gaps large enough to miss job timeouts, triggering REJECT_STALE on every third submission.

5. Configuring “--farm-recheck 500” in lolMiner while connected to a low-latency pool with sub-200ms job propagation causes premature job abandonment and repeated submissions of obsolete work.

Common Questions and Direct Answers

Q: Does a high reject rate always indicate hardware failure?A: No. Hardware failure typically manifests as zero accepted shares or kernel panics. High rejection rates most often stem from configuration mismatches or time sync issues.

Q: Can I see the exact reason for each rejected share in real time?A: Yes. Enable verbose logging in your miner (e.g., “-v” flag in BFGMiner) and monitor stderr output for stratum reject messages containing raw error codes and hex-encoded job IDs.

Q: Why do rejections spike after updating my mining OS?A: OS updates may reset NTP services, downgrade OpenSSL libraries used for TLS handshakes, or modify default stratum port binding behavior—each affecting share validity.

Q: Is there a way to test share submission logic without consuming electricity?A: Yes. Use stratum-tester tools like “stratum-sim” to replay captured job submissions against local mock pools and validate payload structure independently of hardware.