Editing LRS dataset: Error code:-2147217146 'The version could not be located' on startReading query

[Sergio]

Hi all,

I'm facing with the issue when trying to open editing session according to this guide: https://developers.arcgis.com/rest/services-reference/enterprise/start-reading 

I'm trying to send following request: 

https://myportalUrl/server/rest/services/myServerFolder/myPublishedLRS/VersionManagementServer/versi... of default version for my feature service}/startEditing

and pass as form-data sessionId (generated GUID), token (generated on portal using user who is editor) and f=json, but get this JSON in response:

{

    "success": false,

    "error": {

        "extendedCode": -2147217146,

        "message": "The version could not be located",

        "details": []

    }

}

Guid of default version is 100% correct - I've copypasted it from response on this query: https://myportalUrl/server/rest/services/myServerFolder/myPublishedLRS/VersionManagementServer/versi...and also tried with and without curly brackets.

Database is branch versioned and is LRS dataset. Actually I'm trying to follow this video: https://www.youtube.com/watch?app=desktop&v=VQzW-EZCEKc but stuck with the above error. Maybe I'm using wrong version GUID?

Thank you in advance!