What are the permission you given to your app? Have you executed all the endpoints calls and permission applied?
I have 2 permission set up as seen in snapshot. I am calling read log using below endpoint.
https://platform.devtest.ringcentral.com/restapi/v1.0/account/~/extension/~/message-store?availability=Alive&availability=Deleted&availability=Purged&dateFrom=2021-04-01&dateTo=2021-04-12&direction=Inbound&direction=Outbound&messageType=SMS&messageType=Text&page=1&perPage=100";
You read the message-store, you need the "ReadMessages". You don't read the call-log, so you don't need the "ReadCallLog". You also need to call the 'extension/sms' to send at least 5 messages.
We had a similar issue! The Graduation Requirements were not very clear.
It turned out our problem was we didn't include the scope named: "Read Messages", but there was no communication about that in UI.