Handling Failed Calls

Improving your connection rate is crucial for campaign success. This guide covers why calls fail, how to configure retries effectively, and how to analyze your results.

Why calls fail

Understanding failure reasons helps you configure better retries:

Outcome	Cause	Retry helps?
Busy	Recipient on another call	Yes, likely
No Answer	Recipient unavailable	Yes, try different time
Rejected	Recipient declined call	Maybe, depends on reason
Voicemail	Machine answered	Depends on goal
Network Error	Technical issue	Yes, usually temporary

Measuring your baseline

Before optimizing, measure your current performance:

curl -X GET /program-executions/EXECUTION_ID \
  -H "Authorization: Bearer YOUR_API_KEY"

Calculate your connection rate:

Connection Rate = contactsCompleted / totalContacts × 100

Typical benchmarks:

• First attempt: 20-40% connection rate

• With 1 retry: 30-50%

• With 2-3 retries: 40-60%

Your results will vary based on audience, timing, and industry.

Choosing a retry strategy

No retries

{ "type": "none" }

Use when:

• Testing flows

• One-shot notifications

• You'll handle retries externally

• Very time-sensitive messages

Fixed delay

{
  "type": "fixed_delay",
  "delayMinutes": 30,
  "maxRetries": 2
}

Use when:

• Standard campaigns

• Predictable retry timing needed

• Consistent recipient behavior expected

Recommended settings:

Urgency	Delay	Max Retries	Total Attempts
High	15 min	3-4	4-5
Medium	30-60 min	2-3	3-4
Low	120+ min	1-2	2-3

Scheduled

{
  "type": "scheduled",
  "retryDates": [
    "2025-01-20T10:00:00Z",
    "2025-01-20T15:00:00Z",
    "2025-01-21T10:00:00Z"
  ]
}

Use when:

• Different times of day might work better

• Compliance requires specific timing

• Multi-day campaigns

• Weekend/weekday differences matter

Optimizing retry timing

Finding the best times

Track which retry times produce the best results:

Morning (9-11 AM): Often best for business contacts
Midday (12-2 PM): Lower answer rates (lunch)
Afternoon (2-5 PM): Good for most audiences
Evening (5-8 PM): Best for consumer contacts

Day of week patterns

• Monday: Often busy, moderate answer rates

• Tuesday-Thursday: Generally best days

• Friday: Lower afternoon rates

• Weekend: Varies widely by audience

Spacing your retries

Attempt 1: Campaign start
Attempt 2: +30-60 minutes
Attempt 3: Different time of day
Attempt 4: Next day

This gives you coverage across different availability patterns.

Combining retries with pause windows

Retries respect pause windows. Configure them together:

{
  "retryStrategy": {
    "type": "fixed_delay",
    "delayMinutes": 60,
    "maxRetries": 3
  },
  "pauseWindows": {
    "monday": [
      { "startAt": { "hour": 12, "minute": 0 }, "endAt": { "hour": 14, "minute": 0 } },
      { "startAt": { "hour": 18, "minute": 0 }, "endAt": { "hour": 23, "minute": 59 } }
    ]
  }
}

This ensures retries don't happen during lunch or after hours.

Analyzing retry results

Call reports

Get detailed attempt information:

curl -X GET /call-report/JOB_ID \
  -H "Authorization: Bearer YOUR_API_KEY"

Response shows all attempts:

{
  "attempts": [
    { "attempt": 1, "outcome": "busy", "call": { "status": "busy" } },
    { "attempt": 2, "outcome": "no_answer", "call": { "status": "no_answer" } },
    { "attempt": 3, "outcome": "completed", "call": { "status": "completed" } }
  ]
}

Metrics to track

Per-attempt metrics:

• Connection rate per attempt number

• Time of day correlation

• Day of week correlation

• Outcome distribution

Campaign metrics:

• Overall connection rate

• Average attempts needed

• Retry conversion rate (failed → success)

Retry conversion analysis

Calculate how effective your retries are:

Retry Conversion Rate = (Contacts completed after retry) / (Contacts retried) × 100

If your retry conversion rate is low (<10%), consider:

• Different retry timing

• Fewer retries (save resources)

• Different audience segmentation

Handling persistent failures

Some contacts never connect. After exhausting retries:

1. Export failed contacts

2. Analyze patterns

   • Same phone number format?

   • Specific regions?

   • Certain times?

3. Take action

   • Remove invalid numbers

   • Try alternative channels (SMS, email)

   • Flag for manual follow-up

Identifying patterns

Failed contacts by outcome:
- 60% no_answer → Try evening hours
- 30% busy → More retries might help
- 10% rejected → Likely wrong numbers

A/B testing retry strategies

Test different strategies to find what works:

Test setup

1. Split your audience into test groups

2. Create separate programs with different strategies

3. Run simultaneously

4. Compare results

Example comparison

Group A:

{ "type": "fixed_delay", "delayMinutes": 30, "maxRetries": 2 }

Group B:

{ "type": "fixed_delay", "delayMinutes": 60, "maxRetries": 3 }

Group C:

{
  "type": "scheduled",
  "retryDates": ["2025-01-20T15:00:00Z", "2025-01-21T10:00:00Z"]
}

Measuring results

After campaigns complete, compare:

Group	Connection Rate	Avg Attempts	Resource Usage
A	45%	1.8	180 calls
B	52%	2.4	240 calls
C	48%	2.1	210 calls

Choose based on your priorities (connection rate vs. efficiency).

Advanced techniques

Progressive retry spacing

Increase delay between attempts:

{
  "type": "scheduled",
  "retryDates": [
    "2025-01-20T10:30:00Z",  // +30 min
    "2025-01-20T12:00:00Z",  // +90 min
    "2025-01-20T15:00:00Z"   // +180 min
  ]
}

Useful when you don't want to seem aggressive.

Time-zone aware scheduling

For contacts across time zones:

1. Segment audience by region

2. Create separate programs

3. Schedule based on local time

Outcome-based routing

Use flow conditions to handle voicemail differently:

{
  "type": "dial",
  "config": { "enableAMD": true },
  "outputs": {
    "onAnswer": "human-flow",
    "onVoicemail": "leave-message"  // Instead of retry
  }
}

Best practices summary

1. Start with moderate retries - 2-3 retries, 30-60 minute delay

2. Use pause windows - Respect recipient time

3. Track your metrics - Measure before and after changes

4. Test different approaches - A/B test strategies

5. Analyze failures - Understand why contacts don't connect

6. Iterate - Continuously improve based on data

Common mistakes

• Too many retries - Annoying recipients, wasting resources

• Retrying too quickly - Situation hasn't changed

• Ignoring time zones - Calling at inappropriate hours

• Not measuring - Can't improve what you don't track

• One strategy for all - Different audiences need different approaches

Next steps

• Retry Strategies - Complete configuration reference

• Pause Windows - Timing controls

• Executions - Monitoring progress