Delay Until executes successfully but WhatsApp message is not sent consistently after scheduled time

Hi Pabbly Support,

I have created a workflow to send WhatsApp reminder messages using Google Sheets, DateTime Formatter, Delay by Pabbly, and AiSensy.

Workflow:
Google Sheets (New or Updated Spreadsheet Row) → DateTime Formatter (-1 Day) → DateTime Formatter (-30 Minutes) → Delay by Pabbly (Delay Until) → AiSensy (Send WhatsApp Template)

What I expect:

• When a new row is added/updated in Google Sheets, the workflow should schedule reminders.
• The first reminder should be sent 1 day before the session.
• The second reminder should be sent 30 minutes before the session.

Example:

• Session DateTime: 2026-07-26 14:43:00
• 1-day reminder: 2026-07-25 14:43:00
• 30-minute reminder: 2026-07-26 14:13:00

The DateTime Formatter calculates these values correctly.

Issue:

• The Delay step returns Success and shows "Delayed until..." with the correct date/time.
• However, after the scheduled time passes, the WhatsApp message is sometimes not sent.
• In another test, I unexpectedly received the same WhatsApp message three times even though I expected only one message.
• The workflow behavior is inconsistent. Sometimes the delayed message is delivered, and sometimes it is not.
  Task History Status: All executions show Success in Task History. There are no failed steps. However, even though the workflow completes successfully, the WhatsApp reminder is not always received on the recipient's phone. In some tests, the reminder was not delivered at all, while in another test, the same reminder was delivered three times. Please investigate why the workflow reports success but the WhatsApp delivery is inconsistent.

Could you please check:

1. Whether the Delay step is correctly resuming the workflow after the scheduled time.
2. Whether there is any issue with delayed task execution.
3. Why duplicate WhatsApp messages were sent in one test.
4. Whether there are any workflow configuration issues from your side.

Thank you.

Hello,

Thank you for reaching out and providing detailed context.

To help us investigate why the delayed messages are behaving inconsistently and why duplicate messages occurred, could you please share the Workflow URL of the workflow in question?

Once we have the direct link to your workflow, we can inspect the exact setup, task execution logs, and step configurations to pinpoint the issue.

Looking forward to your reply so we can get this resolved for you.

Hello,

Thank you for sharing the workflow URL.

Upon reviewing your workflow configuration, we found why the delay execution timing is not aligning with your expected schedule:

The Delay by Pabbly (Delay Until) step inherently interprets all date and time values in UTC (UTC+0) timezone.

Why this affects your messages:

• When you map a date/time into the Delay step, it treats that timestamp as UTC time rather than your local time (such as IST).

• Because of this timezone difference, the workflow pauses until that exact timestamp occurs in UTC, causing the execution to resume earlier or later than intended (or appear inconsistent).

How to resolve it:

1. In your DateTime Formatter step (or an additional DateTime Formatter step), convert your calculated target date/time to the UTC Time Zone (UTC+0).

2. Map the resulting UTC date/time into the Delay Date field in your Delay by Pabbly step.

Once the date/time passed to the Delay step is explicitly formatted in UTC, the workflow will resume and deliver your WhatsApp messages accurately at the exact desired time.

Please update the mapping and let us know if you need any further assistance!