My permission to the SmartObject:

Do you see the smartobject if you browse to the following URL via browser?

https://nintexdemo.ru/api/odata/v3

As a test, can you create a simple SmartBox SmartObject then add it to the list of Selected SmartObjects, and see if that works?

Hi DmitryR,

Can you enable Odata tracing and see if that will give us any more information?

https://community.nintex.com/t5/Internal/How-to-enable-Odata-Tracing-for-SmartObject-Odata-API/ta-p/203703

Khanh your link doesn't work for me, an issue is: You do not have sufficient privileges for this resource or its parent to perform this action.

I turned on OData tracing, please check log file in attachment.

I created the new SmartObject "PowerBI_Test2". 

Physical path to the SmartObject "[Program Files]K2WebServicesAPISmartObjectService.ODatav3PowerBI_Test2"" isn't exist, and folder "v3" isn't exist too.

From your K2 Management, go to Authentication > Claims > Issuers. What issuer are you using? Also check the Realms page to see which realm is using which issuer.

Checking this because recently I came across a case where an organization's users are using ADFS to login. If they try to open the OData API with a user that uses the K2 security label, the OData API works.

Hello,

please check screenshots below.

Issuers:

Realms:

The problem is related to Russian as the main system language.

Solution is:

1. Open the "Web.config" file by path: [Program Files]K2WebServicesAPISmartObjectService.Odata
2. Find: "<system.web>"
3. After "<system.web>" in new line add: "<globalization culture="en-US" uiCulture="en-US" />"
4. Save file
5. Restart IIS cmd: iisreset