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The trigger for this Zap is when a new appointment is created in Thryv. I want to delay steps until the end of that appointment, but that step keeps failing, always with the same error:

Failed to schedule a delay

Object of type datetime is not JSON serializable

I’ve tried the following things to fix this:

  • Formatter by Zapier, to reformat the date time into every conceivable option, including manual options. None of them work. 
  • Code by Zapier, in an attempt to force the date time into a string value via Python
  • Formatting twice, to add a space in date time, to try to force a string, etc.

None of these are working. No matter what I do, it has the same error when testing. 

Any ideas? Should I be formatting it differently? How do I make the Zap wait until the end time of this appointment?

 

FYI - In the screenshot, step 2 is a simple filter to make sure that only certain appointments go through.
 

 

 

Hi ​@tvvlivermore 

Check the Zapier Status page for recent incidents related to this that should now be resolved:

https://status.zapier.com/#incidents-list


Hi there, ​@tvvlivermore 👋

It seems like that error was likely related to the incident Troy referenced, which was resolved on May 19: https://status.zapier.com/incidents/d1v8pjnvth49. As that was a day before you posted here, I just wanted to double-check—are you still seeing those “Object of type datetime is not JSON serializable” errors in your Zap, or have the errors stopped appearing now?

Want to make sure it’s definitely fixed, so please keep us posted on how it’s going! 🙂


Sorry I didn’t reply to the last response. Yes, I saw the reported error and fix, and was able to run it successfully. Thank you!


That’s an amazing news ​@tvvlivermore! We’re glad to hear that the issue is now resolved!

If you have any other questions, please don’t hesitate to reach out to the Community. We’re always happy to help! 🤗


No worries, ​@tvvlivermore! Thanks so much for confirming—really pleased it’s sorted. 😁🎉

Hope you have a great day!


If the Delay step in Zapier is not reading your date/time field correctly, it's likely due to formatting issues. Zapier requires a standardized date/time format, such as ISO 8601 (YYYY-MM-DDTHH:MM:SSZ). To fix this:

  1. Use a Formatter step before the Delay step.

  2. Choose "Date/Time" → "Format" and convert your field to a Zapier-friendly format (e.g., 2025-06-10T14:00:00Z).

  3. Then pass the formatted date to the Delay step.

Also, double-check your time zone settings in Zapier to ensure accurate delays.


Steve, did you see the comments above? The issue was an internal error in Zapier.


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