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Best Practices for Ringless Voicemail (RVM) Campaigns and Improving Delivery Rates

To maximize results from your Ringless Voicemail (RVM) campaigns, follow these key guidelines regarding phone numbers, recordings, and contact lists. This guide outlines best practices to improve delivery rates and prevent common issues.

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What Delivery Rate Should You Expect?

RVM delivery rates depend heavily on the quality of your contact list.

  • A delivery rate of approximately 30% is typical for average contact lists.

  • Lower rates usually indicate issues with:

    • Contact data

    • Phone numbers used for sending

    • Message quality


Why Are My Voicemails Failing?

Here are the most common reasons:

1. Sending too many RVMs at the same time

Sending more than 50 RVMs per hour from a single local number may result in the number being flagged by carriers for high, non-human call volume.

2. Recording Quality

Carriers use automated systems to detect spam-like messages. Recordings that sound:

  • Robotic

  • Repetitive

  • Low quality

are more likely to be blocked.

3. Contact List Issues

If your contact list includes outdated or invalid numbers, your delivery rates will decrease significantly.


Failure Types

After a campaign, you may see different failure reasons:

  • No Answer
    The number is invalid or no longer in service. We recommend removing these numbers from your list.

  • Voicemail Not Detected
    The number is valid, but one of the following may apply:

    • Voicemail may not be set up

    • Inbox may be full

    • The carrier may be blocking the call

Recommended action: Retry at a later time.


How to Improve Your Delivery Rates

Use the Right Number

  • For large contact lists, avoid sending high volumes from a single local number. Instead, use:

    • Toll-free numbers (best for scale)

    • Multiple numbers (number pools) to spread traffic

Keep Recordings Fresh

  • Update your message weekly or monthly

  • Use a natural, human tone

  • Avoid using the same script for extended periods.

Maintain a Clean Contact List

  • Remove failed numbers after each campaign

  • Regularly update and verify your data


Should I Retry Failed Voicemails?

Be selective when retrying:

❌ Do not retry “No Answer” failures, as these are likely invalid numbers.

✅ Retry “Voicemail Not Detected” failures after approximately seven days.

Retrying all failures may negatively impact your overall delivery performance.


Avoid Spam Labeling

Carriers monitor calling behavior and may flag suspicious activity.

To minimize this risk, consider the following:

  • Spread volume across multiple numbers

  • Avoid sudden spikes in sending

  • Keep your messaging natural and updated

You can also register your numbers on the Free Caller Registry to help reduce spam labeling.


Key Takeaways

  • Use toll-free or multiple numbers to achieve better results when broadcasting to lists larger than 1,000 contacts a day

  • Limit the number of contacts you send broadcasts to each hour by using our throttling feature, “Advanced Scheduling.”

  • Keep your recordings natural and updated

  • Regularly clean your contact lists

  • Only retry valid numbers


If you need assistance improving your RVM performance, our support team is available to help.

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