Hi @Kashif Akram,
If your SSRS setup similar to the one below. You're likely running into a common SSRS Reporting Service Double Hop (aka Negotiate / SPNego / Kerberos/ SSO) issue.
Clients e.g. PCs -> SQL Server A (Hop 1) with SSRS -> SQL Server B (Hop 2) contains DBs where your SSRS data sources are pointing to.
There're 2 solutions to this.
Solution 1 is to hardcode credential in each Data Source.
Solution 2 is to configure Kerberos Authentication (SPN + Account Delegation). Check it out here: https://redmondmag.com/articles/2010/08/23/reporting-services-double-hop-authentication.aspx
Regards, Zoe Hui
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