Hi everyone,
I’m working on a feature, where single button triggers a set of actions that grants permissions across related parent and child workflows, and delegates active task to other user using REST API.
I'm currently facing a frustrating issue with the task delegation API using the endpoint POST /api/data/v6.0/db/{dbId}/elements/{elementId}/admin/tasks/assignment
When I use this endpoint via Swagger, the task delegation executes successfully. Here's a sample of the payload that works perfectly in Swagger:
{
  "task": {
    "userId": "xxx@gmail.com"
  },
  "delegatedTask": {
    "userId": "yyy@gmail.com",
    "description": "Changed by REST Web Service",
    "sendEmail": false,
    "emailMessage": ""
  }
}
It returns 200 OK with the message Task was delegated.
When I try to execute the exact same request from a “Call REST Web Service” action within a button, I consistently get a 500 Internal Server Error with timeout details, even though curl is identical as the one from swagger. 
Error log:
Public Api POST /api/data/v6.0/db/1/elements/61445/admin/tasks/assignment
Status code: 500 Error message: Execution Timeout Expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.
The statement has been terminated. Callstack: Microsoft.Data.SqlClient.SqlException (0x80131904): Execution Timeout Expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.
Anyone got an idea what could be causing this error?
EDIT1:
Interestingly, when I change the userId in the payload to a non-existent user, the response returns:
409 Conflict
{
  "type": "ValidationError",
  "description": "User zzz@gmail.com does not exist or no tasks were found for this user.",
  "errorGuid": "d0bdb551-8432-48a9-b011-f7e9cf10fb85"
}
But when the userId is correct and points to the actual task owner, the same request results in a 500 Internal Server Error. So the request passes validation and is received, but something goes wrong deep in the backend logic
                        
 
                                     
                                



 
                                