Agent Skills: Lindy Common Errors

Lindy Common Errors

Overview

Troubleshooting guide for Lindy AI agent errors. Lindy agents fail at specific points in the workflow: trigger reception, action execution, condition evaluation, or exit condition evaluation. This guide covers each failure class.

Prerequisites

• Access to Lindy dashboard (https://app.lindy.ai)
• Ability to view agent Tasks tab for error details
• For webhook debugging: curl installed

Trigger Errors

Webhook Not Firing

Symptoms: No task created when webhook is sent Causes & Solutions: | Cause | Diagnostic | Fix | |-------|-----------|-----| | Wrong URL | Check webhook URL in agent config | Copy exact URL from trigger settings | | Missing auth | curl -v shows 401 | Add Authorization: Bearer <secret> header | | Agent inactive | Dashboard shows agent paused | Activate the agent | | Filter blocking | Trigger filter too restrictive | Review filter conditions, test with broader filter | | Wrong HTTP method | Using GET instead of POST | Lindy webhooks require POST |

# Diagnostic: Test webhook connectivity
curl -v -X POST "https://public.lindy.ai/api/v1/webhooks/YOUR_ID" \
  -H "Authorization: Bearer YOUR_SECRET" \
  -H "Content-Type: application/json" \
  -d '{"test": true}'
# Expect: 200 OK

Email Trigger Not Activating

Symptoms: Emails arrive but agent does not wake up Solutions:

1. Verify Gmail/Outlook authorization is current (re-authorize if expired)
2. Check label filter — Lindy Email Received trigger can filter by label
3. Confirm email matches trigger filter conditions (sender, subject, etc.)
4. Check that agent is active, not paused

Schedule Trigger Missed

Symptoms: Agent did not run at scheduled time Solutions:

1. Verify timezone settings match your expectation
2. Check credit balance — agents stop if credits exhausted
3. Review schedule configuration (daily vs weekday vs custom)

Action Errors

Slack Send Failed

| Error | Cause | Fix | |-------|-------|-----| | Channel not found | Channel name wrong or private | Use exact channel name; ensure bot is invited | | Not authorized | Slack token expired | Re-authorize Slack in Lindy integrations | | Rate limited | Too many messages | Reduce trigger frequency or batch messages |

Gmail Send Failed

| Error | Cause | Fix | |-------|-------|-----| | Authentication expired | OAuth token expired | Re-authorize Gmail in Settings | | Recipient rejected | Invalid email address | Validate email format in prior step | | Draft not found | Thread ID mismatch | Verify thread context in action config |

HTTP Request Action Failed

| Error | Cause | Fix | |-------|-------|-----| | Connection refused | Target API down | Verify target URL is reachable | | 401 Unauthorized | Auth header misconfigured | Check Authorization header value | | Timeout | Target API slow | Increase timeout or optimize target endpoint | | SSL error | Invalid certificate | Ensure target uses valid HTTPS cert |

# Diagnostic: Test target API independently
curl -v -X POST "https://api.yourapp.com/endpoint" \
  -H "Content-Type: application/json" \
  -d '{"test": true}'

Run Code Action Failed

| Error | Cause | Fix | |-------|-------|-----| | Import error | Library not available | Use only pre-installed libraries (pandas, numpy, etc.) | | Type error | Input variable is string | Cast explicitly: int(var), json.loads(var) | | Timeout | Long-running computation | Optimize code; avoid infinite loops | | Return value empty | No return statement | Add explicit return with result data |

Knowledge Base Returns No Results

| Cause | Fix | |-------|-----| | Fuzziness at 0 (keyword only) | Increase to 100 for semantic search | | Content not indexed | Trigger Resync Knowledge Base action | | Query too vague | Switch field to AI Prompt mode with specific instructions | | File too large (>20MB) | Split into smaller files |

Agent Step Errors

Agent Loops Indefinitely

Cause: Exit conditions never satisfied Fix: Add measurable, achievable exit conditions:

Primary: "Found at least 3 relevant results"
Fallback: "Made 5 search attempts without finding results"

Agent Picks Wrong Condition Branch

Cause: Ambiguous condition prompt Fix: Make conditions mutually exclusive with clear criteria:

Branch A: "Go down this path if the email mentions billing, payment, or invoice"
Branch B: "Go down this path if the email mentions a technical issue, bug, or error"
Branch C: "Go down this path for all other topics"

Credit Overrun Warning

Symptom: "Task using more resources than expected" pause Cause: Agent step consuming too many credits (complex reasoning) Fix: Simplify prompt, reduce available skills (2-4 max), use smaller model

Debugging Checklist

1. [ ] Open agent Tasks tab — find the failed task
2. [ ] Click into the task — review each step's input/output
3. [ ] Identify the failing step (red indicator)
4. [ ] Check the step's error message and stack trace
5. [ ] Verify integration authorizations are current
6. [ ] Test the trigger independently (curl for webhooks)
7. [ ] Test the action independently (manual run)
8. [ ] Check credit balance — insufficient credits halt execution

Error Handling

| Error Category | HTTP Status | Retry? | Notes | |---------------|-------------|--------|-------| | Auth failure | 401 | No | Re-authorize integration | | Rate limited | 429 | Yes | Wait for credit reset | | Agent not found | 404 | No | Verify agent exists and is active | | Action timeout | 504 | Yes | Simplify step or increase timeout | | Run Code error | 500 | Maybe | Fix code, then retry | | Credit exhausted | 402 | No | Upgrade plan or wait for monthly reset |

Resources

• Lindy Documentation
• Lindy Community
• Lindy Status

Next Steps

Proceed to lindy-debug-bundle for comprehensive diagnostics.