Connect access to rest/agile

Hello everyone,

Im during process of developing my own app that is an extension to Jira, using Connect.

Im not sure if I am missing something as I went through the docs, but I can’t manage to get access to rest/agile (jira software cloud) endpoints from Connect.
E.g.

GET `/rest/agile/1.0/board/${selectedBoardId}/sprint`,
-> 403

rest/api (jira cloud platform) obviously works ok. I am using built-in AP.request. from the FE side.
Is it possible at all?

Regards,
Paweł