Unable to send email using Send HTTP Request to SharePoint when specifying some users in the TO field

[ajohny1]

Unable to send email using "Send HTTP Request to SharePoint" when specifying some users

12 hours ago

We have a flow which send emails using  "Send HTTP Request to SharePoint".

I have added "All Users" and "Everyone Except external users" to the sharepoint site. 

For some emails, when we specify in the To field, the flow fails with the below message:

{

  "status": 400,

  "message": "The e-mail message cannot be sent. Make sure the e-mail has a valid recipient.\r\nclientRequestId: 84eff124-6567-4e19-bb7d-c4305f6a33a8\r\nserviceRequestId: 13976da0-b0ec-1000-aa21-54d3a498bc74",

  "source": "https://xxxxxxxx.sharepoint.com/teams/PowerPlatformEmail/_api/SP.Utilities.Utility.SendEmail",

  "errors": [

    "-2130242040",

    "Microsoft.SharePoint.SPException"

  ]

}

It works fine for some users.. The same users which is failing is working fine with some other share point site.

This is the message body

{
'properties':
{
'From' : 'noreply@xxx.com.au',
'To': ['abc@xxx.com,au'],
'Subject': ' Test Email ',
'Body': 'Email Body '
}
}

Any idea what is missing here ?