Replication jobs are not working and there are many errors showing the App ID (Service Account) doesn't have access to different Directory connectors!
The current user 'Service account' does not have required permission 'read' to load item: d31143c8-4a75-442b-88cf-2778e6d3a4bb
Release : 8.x
Service account doesn't have enough permissions to the SQL server.
The issue got resolved after adding the service account to the SQL servers administrators. (In Windows Server User Accounts).
For other SQL rights which are needed for the Application Identity service account (or SQL account), you can check the following article:
KB 181352 "What SQL rights are needed for the Application Identity service account (or SQL account)?"