Improve investigation and messaging for "Transaction not found" error

[jamespepper81]

Users sometimes see a "Transaction not found" error when looking up transactions. This prevents them from viewing transaction details and causes confusion. We need to improve both the investigation guidance and the UI messaging.

What happens (actual)

• The UI displays "Transaction not found" when a lookup fails.
• No additional guidance or links are shown to help the user verify the TXID externally or retry.
• No obvious way for support to gather required diagnostic data from the reporter.

What should happen (expected)

• Clearer user-facing message explaining possible causes (typo, pending mempool transaction, indexing delay) with actions to verify (link to public explorer, retry button).
• Capture and log context for failed lookups (TXID, request timestamp, backend response, user agent) to aid investigation.
• Provide reproducible steps and necessary metadata in the issue so engineers can debug.

Steps to reproduce / info requested from reporter

1. TXID that produced the error.
2. Exact steps used to trigger the error (search bar, direct URL, imported TXID, API call).
3. Full browser URL and any query parameters.
4. Timestamp (UTC) when the error occurred.
5. Whether the TXID appears on a public block explorer (link to mempool.space / blockchain.com).
6. Optional: screenshot and browser user agent.

Investigation checklist (engineers)

• Confirm TXID format & existence on public explorers.
• Check backend/indexer logs for the request timestamp to find errors/timeouts.
• Verify search/routing logic and response validation when backend returns null/empty.
• Check mempool/backend indexing pipeline for delays or recent failures.
• Confirm whether caching or edge routing might return stale 404s.
• If applicable, correlate with deployment/maintenance windows.

Immediate UX improvements suggested

• Replace generic "Transaction not found" with a contextual message:
  • Short explanation of common causes (typo, pending mempool, index delay).
  • Buttons/links:
    • Retry lookup
    • View on mempool.space (open in new tab)
    • Report this TXID to support (pre-populated with TXID & page URL)
• Show a small “we’re checking” state for very recent TXIDs (e.g., <10 min) with an automatic retry suggestion.

Logging / telemetry

• Record failed lookup events with:
  • TXID
  • request timestamp
  • endpoint/backend response code
  • indexer status at time of request
  • user agent / app version
• Persist a short-term queue of failed TXIDs to analyze for patterns.

Labels, assignee, and priority

• Labels: bug, investigation, ux-improvement
• Assignee: @jamespepper81
• Priority: P2 (investigate, add logging, and improve UX)

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