Getting a 400 - bad request response when updating the External ID of a contact.

@roy s11​, do you have any idea what might be causing this?

I am also facing exact same issue. do you know any workarounds ?

Hey @user147​ Racheal from the support engineer team here👋 

How close together are you making these create and update calls? If they are too close together the user might not be created yet and we can't find a user to update. When you say you leave the external ID out and it works, what other data is being sent through?

@racheal​  since I am also experiencing the same issue more recently. I can confirm that these calls 1. creating a contact without external_id and 2. Updating contact for external_id are made with significant delay. 2 to 3 days later.

for your second question, I am sending some basic fields and a few custom fields as well

Hey @rasikh​ Sorry I didn't tag you there!

That is odd, I'm not running into any trouble updating a contacts external_id, even if it was unknown previously. To walk you through my steps, I create the user using the create user endpoint:

I then grab that id and make an update call, to update the external_id:

A couple questions here- can you confirm that you are setting the appropriate headers? Additionally, are you creating/updating a lead or user?