Failed to update direct query dataset from REST api Datasource

api url : https://api.powerbi.com/v1.0/myorg/groups/xxxxxxxxxxxxxxxx/datasets/1xxxxxxxxxxxxxx/Default.UpdateDatasources"

Added provided json for connection details. Output as error shown below. please provide feedback ??

Result as :

object(stdClass)#2 (1) {
  ["error"]=>
  object(stdClass)#7 (3) {
    ["code"]=>
    string(10) "BadRequest"
    ["message"]=>
    string(11) "Bad Request"
    ["details"]=>
    array(2) {
      [0]=>
      object(stdClass)#8 (2) {
        ["message"]=>
        string(101) "Bad JSON escape sequence: \I. Path 'updateDetails[0].connectionDetails.server', line 12, position 35."
        ["target"]=>
        string(66) "updateDatasourcesRequest.updateDetails[0].connectionDetails.server"
      }
      [1]=>
      object(stdClass)#9 (2) {
        ["message"]=>
        string(50) "'updateDatasourcesRequest' is a required parameter"
        ["target"]=>
        string(24) "updateDatasourcesRequest"
      }
    }
  }
}