Update User API - Cloudflare Response Received

Hello.  I am trying to use the update user API (https://developer.khoros.com/khoroscommunitydevdocs/reference/update-a-user) and am receiving a Cloudflare "Sorry, you have been blocked" response.

I am using Postman to send a PUT request to my community domain as follows:

https://community_domain/api/2.0/users/user_id

Of course substituting community_domain and user_id with valid values.  I am passing the session key in the header via li-api-session-key and application/json via Content-Type.

The user that I retrieved the session key for is defined as an admin and has access to all.

The body of the request is simple:

The response status from the PUT is 403 with the response body being a Cloudflare "Attention Required" page.  I have tried the request from multiple IP addresses.

Ideas?  Thanks in advance.