I keep getting a 403 error while trying to simply fetch available spaces

[Prisme Dev]

I'm using a cloud app secured with Oauth2 flow with all the granular scopes enabled to get spaces on the correct "Use App On" section (the domain I'm trying to reach). 

I then make a curl with the code received to receive my access token, but my request can't work and I always get this msg :

"statusCode": 403,

"message": "com.atlassian.confluence.mvc.rest.common.exception.StacklessResponseStatusException: 403 FORBIDDEN \"Request rejected because caller cannot access Confluence\""

Here's a exemple I made out of Postman :

GET https://myclouddomain.atlassian.net/wiki/rest/api/space
And in the Authorization tab : Bearer Token -> Token : the token I received