Problem with permissions in REST API

Jira Development
1

Hello!
I created dev cloud with project and some tasks for test.
After successful authorization I tried to search for issues with access token (POST):

https://mydevcloud.atlassian.net/rest/api/3/search

With body

{
  "jql": "assignee = currentUser()",
  "startAt": 0,
  "maxResults":110,
  "fields": [
    "timespent",
    "timeoriginalestimate",
    "resolutiondate",
    "worklog",
    "summary"
  ],
  "fieldsByKeys": false
}

As result I got

{
    "message": "Client must be authenticated to access this resource.",
    "status-code": 401
}

How is it possible?
Exactly, I authorized with suitable scope for my dev cloud as described in article.

For test I tried to do it via Postman after getting token via my app.
Please help.