Investigating Why a Single Send Was Sent to Zero Recipients in SendGrid

Objective

This article explains how to investigate a scenario where a Twilio SendGrid Single Send appears to have been sent to no contacts. Using the Single Send Dashboard and backend data queries, you can determine which contact list the Single Send targeted and diagnose if the campaign had an empty recipient list due to contact upload timing or other factors. Keywords in this article include: Single Send, no contacts, List ID, Single Send Dashboard, mc_singlesend, mc_contact_list.

Product

Twilio SendGrid Marketing Campaigns

User Account Permission/Role(s) Required 

• Twilio SendGrid TSE or equivalent permissions (for dashboard access)
• Access to internal tools/queries in Snowflake and Splunk (for support or operations teams)

Procedure 

1. Verify the Target List for the Single Send

1. Go to the Single Send Dashboard at: Splunk Single Send Dashboard
2. Locate and select the relevant Single Send campaign by its ID.
3. In the General Single Send Information section, check for any associated List IDs.
   • If there are no List IDs listed, the Single Send was configured to send to all contacts.
   • If there is a List ID, proceed with the next steps.

2. Check Single Send Timing in Snowflake

1. Run the following query in Snowflake, replacing XXX with the user ID and 'SS ID HERE' with the Single Send ID:

   SELECT *
   FROM mc_singlesend
   WHERE user_id = 'XXX'
     AND array_contains('SS ID HERE'::variant, singlesend_ids)

2. Review the result to find the send_at timestamp, which shows when the Single Send was dispatched.

3. Check List Upload Timing in Snowflake

1. Run this query, replacing XXX with the user ID and 'MC LIST ID HERE' with the List ID found earlier:

   SELECT *
   FROM mc_contact_list
   WHERE user_id = 'XXX'
     AND array_contains('MC LIST ID HERE'::variant, list_ids)

2. Review the result for the list’s upload or creation timestamp.

4. Compare the Timestamps

• If the Single Send’s send_at timestamp is very close to the list upload timestamp, this may indicate that the contact list upload was not fully completed before the Single Send was sent.
• In such cases, the campaign would have had no contacts to send to, resulting in a Single Send sent to zero recipients.

Additional Information 

• If you find no List IDs in the General Single Send Information section, this means the campaign targeted all contacts, and further investigation may be needed if no contacts actually received the send.
• For more on Single Sends, see SendGrid Docs: Single Sends.
• If you need help with these queries or analysis, contact your Twilio SendGrid support team.