It seems that both the Editor and DateReviewCompleted updates must succeed without errors for the 'Send an HTTP request to SharePoint' action to successfully update these columns.
(1) Please check the runtime output and share the output.
- The example below shows the runtime output of a flow attempting to update a person column (Reviewer) and a date column (StartDate).
- The action to update the Reviewer column completed without errors (HasException = false), whereas the action to update the StartDate column failed (HasException = true).
- Note that the 'Send an HTTP request to SharePoint' action ran successfully, but gives the impression that the update was fully successful. You will need to check the runtime output of the "Send an HTTP request to SharePoint" to figure out what is going wrong.
In the screenshot above, Reviewer update succeeded, but StartDate update failed, even though the 'Send an HTTP request to SharePoint' action ran successfully.
On closer inspection of the error message, there was an issue with the date format: "You must specify a valid date within the range of 01/01/1900 and 31/12/8900."
{
"ErrorCode": -2146232832,
"ErrorMessage": "You must specify a valid date within the range of 01/01/1900 and 31/12/8900.",
"FieldName": "StartDate",
"FieldValue": "2025-04-12T11:12:19.3860032Z",
"HasException": true,
"ItemId": 167
}
SharePoint usually expects dates to be in ISO 8601 (yyyy-MM-dd). But it seems that when interacting with the REST APIs using the validateUpdateListItem endpoint, dates must follow the SharePoint site’s regional settings - in my case UK: dd/MM/yyyy.
This is how I have updated the person column and date field. I did not specify any headers:
And here is my sample runtime output.
The StartDate "12/04/2025" will get saved as "2025-04-12" inside SharePoint. The date "2025-04-12" (is actually 2025-04-12T00:00:00) should be interpreted based on the site's regional settings. In my case the site setting region is English (United Kingdom), and the site's time zone is (UTC) Dublin, Edinburgh, Lison, London.
I found that if I changed the site's regional settings to International Date Line West (UTC-12), the StartDate was read as "StartDate": "2025-04-11" - which is correct, 2025-04-12 (London) is 2025-04-11 (International Date Line West).
See also:
Hope this helps.
