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Kindly follow the steps provided below to resolve your issue.
To use data from an Oracle database in your report, you must have a dataset that's based on a report data source of type Oracle. This built-in data source type uses the Oracle Data Provider directly and requires an Oracle client software component. This article explains how to download and install drivers for Reporting Services, Power BI Report Server, Report Builder, and Power BI Desktop.
Go to this link for your reference and other troubleshooting procedures https://learn.microsoft.com/en-us/sql/reporting-services/report-data/oracle-connection-type-ssrs
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