Microsoft Fabric to RStudio Desktop

Howdy! Can you try with the AzureAuth package instead?

GitHub - Azure/AzureAuth: R package for OAuth 2.0 authentication with Azure Active Directory

The main function in AzureAuth is get_azure_token, which obtains an OAuth token from AAD. The token is cached in a user-specific directory using the rappdirs package, and future requests will use the cached token without needing you to reauthenticate.

library(AzureAuth) 
token <- get_azure_token(
   resource="myresource", 
   tenant="mytenant", 
   app="app_id",
    ...
)