OAUTH 2.0 (3LO) not working with Pyhton

[Rishi Sohaney]

I'm developing a Python app , which takes user email from the user and pass to the Jira Cloud through API by using OAuth 2.0 (3LO) to get the list of all projects belongs to the user, however I'm always getting 

Error getting user info: Client must be authenticated to access this resource.

[Mercy]

That error means your app is calling the Jira Cloud REST API before completing the OAuth 2.0 3LO authorization flow. Jira Cloud requires a valid access token tied to the user before any endpoint like `/rest/api/3/project/search` or `/rest/api/3/myself` will respond. You must first direct the user through the Atlassian authorization URL (`) with the correct `client_id`, `redirect_uri`, `scope`, and `response_type=code`, then exchange the returned code for an access token using ` Only that token should be sent in your API requests with the `Authorization: Bearer ` header.