Error in process_response

[bhishwor]

Hi, i am having issue to accessing Microsoft Library. It was working fine but suddenly it stop working and throws an error.
r code:
library(Microsoft365R)

list_sharepoint_sites()
site <-get_sharepoint_site('')
siteF<-get_sharepoint_site('')
siteR<-get_sharepoint_site('')

siteR$list_drives()
drv<-site$get_drive('')

drvPR<-site$get_drive('')

drvFin<-siteF$get_drive('')

drvEv<-siteR$get_drive('')

drvFin$list_files()
Error Message :
Loading Microsoft Graph login for default tenant
Error in process_response(res, match.arg(http_status_handler), simplify) :
Forbidden (HTTP 403). Failed to complete operation. Message:
Access denied.

Can you please let me know how to fix this.