There are no specific errors, but the retention of old data may be highlighted by the size of the database.
The Transaction History deletion relies on the SQL Server Agent job running daily which executes the PurgeHistory stored procedure (within the EVOM database / Programmability / Stored Procedures) to cleanup the tables.
Confirm that the SQL Server Agent is running. The PurgeHistory job history can be seen by going to SQL Server Agent -> Jobs -> EV Monitoring History Purge Job -> Properties or View History.
The job can be run manually by right-clicking the job in SQL Admin and selecting Start job at Step.