Trace ID
trace_93cada83-9eff-4c97-9bff-40455273f3fa
- Amount
- 500 CKB
- Mode
- sandbox
- Latency
- 84ms
- Failure stage
- capacity_probe
- Sender
- fiber-devnet-sender-01
- Receiver
- fiber-devnet-receiver-09
ROUTE_CAPACITY_INSUFFICIENT
Route capacity insufficient
A route was discovered, but the available forwarding capacity was lower than the requested payment amount.
Likely Causes
- Outbound liquidity is below the payment size
- One hop has a lower max HTLC than the payment amount
- The route can carry smaller payments but not this full amount
Suggested Fixes
- Reduce amount to the largest successful replay amount
- Split the payment across multiple paths
- Add outbound route capacity on the constrained hop
Failure Timeline
Lifecycle events captured in milliseconds.
- 0msrequest_receivedinfo
Payment attempt created for 500 CKB
- 8msinvoice_validationsuccess
Invoice fields parsed
- 18msroute_discoveryinfo
Candidate routes loaded from sandbox graph
- 50mspolicy_checkinfo
Route policies evaluated
- 62mscapacity_probewarning
Candidate path capacity: 320 CKB available for 500 CKB request
- 84mscapacity_probeerror
Route capacity insufficient: max forwardable 320 CKB
Replay-to-Fix Results
same_conditions
Original amount, route, peer state, fee limit, timeout, and asset unchanged
The original failure reproduces under the same conditions, confirming the fingerprint is stable.
reduced_amount_80
Reduced amount to 80%: 400 CKB
400 CKB still exceeds the constrained route capacity, so the payment fails again.
reduced_amount_64
Reduced amount to 64%: 320 CKB
320 CKB matches the observed maximum forwardable capacity and settles.
increased_outbound_capacity
Added exact outbound route capacity deficit: 180 CKB
Adding 180 CKB raises route capacity to the original payment amount and removes the constrained hop.
alternate_route
Selected alternate route excluding the failing condition
A route with different hops avoids the original failure point with slightly higher latency.
split_payment
Split payment into 250 CKB + 250 CKB
Splitting widens eligible paths and lowers per-route capacity pressure while preserving the original total amount.
Exportable Debug Report
Markdown and JSON report output for trace reviews and operator handoff.
# FiberTracebox Report ## Trace Summary - Trace ID: trace_93cada83-9eff-4c97-9bff-40455273f3fa - Payment status: replayed - Amount: 500 CKB - Sender: fiber-devnet-sender-01 - Receiver: fiber-devnet-receiver-09 - Mode: sandbox - Latency: 84ms - Failure time: 84ms - Failure stage: capacity_probe - Failure fingerprint: ROUTE_CAPACITY_INSUFFICIENT ## Root Cause A route was discovered, but the available forwarding capacity was lower than the requested payment amount. ## Evidence Source - Trace source: sandbox - Replay mode: deterministic sandbox replay - Live mutation: no - RPC methods observed: not applicable - Observed failure: not applicable - Sandbox events are deterministic and safe for repeatable demos and CI. - Replay-to-Fix changes simulated route conditions without moving funds. ## Timeline | ms | stage | severity | message | | --- | --- | --- | --- | | 0 | request_received | info | Payment attempt created for 500 CKB | | 8 | invoice_validation | success | Invoice fields parsed | | 18 | route_discovery | info | Candidate routes loaded from sandbox graph | | 50 | policy_check | info | Route policies evaluated | | 62 | capacity_probe | warning | Candidate path capacity: 320 CKB available for 500 CKB request | | 84 | capacity_probe | error | Route capacity insufficient: max forwardable 320 CKB | ## Replay Results | strategy | changed condition | result | latency ms | recommended | | --- | --- | --- | --- | --- | | same_conditions | Original amount, route, peer state, fee limit, timeout, and asset unchanged | failed | 91 | no | | reduced_amount_80 | Reduced amount to 80%: 400 CKB | failed | 70 | no | | reduced_amount_64 | Reduced amount to 64%: 320 CKB | success | 58 | no | | increased_outbound_capacity | Added exact outbound route capacity deficit: 180 CKB | success | 66 | no | | alternate_route | Selected alternate route excluding the failing condition | success | 73 | no | | split_payment | Split payment into 250 CKB + 250 CKB | success | 79 | yes | ## Smallest-Fix Recommendation Smallest route-capacity fix: Split the payment into two 250 CKB parts, or reduce amount to 320 CKB. If the operator controls liquidity, add at least 180 CKB outbound route capacity. Confidence: high ## Suggested Next Actions - Reduce amount to the largest successful replay amount - Split the payment across multiple paths - Add outbound route capacity on the constrained hop - Split the payment into two 250 CKB parts, or reduce amount to 320 CKB. - If the operator controls liquidity, add at least 180 CKB outbound route capacity. ## Mode Disclosure Sandbox mode: deterministic simulated Fiber payment conditions are used for repeatable diagnostics.