The user data source credentials do not meet the requirements to run this report or shared dataset error when running reports

Yes, I've seen this. You can set the Credential and Connection Information such that a report is run impersonating the unattended user account. This article explains how to set up this type of report running. This setup is especially useful if you want to use the credentials inside a dynamic connection string (for example when you need to insert the credentials through a parameter).

If you don't want to run using the unattended user account, you should review your DataSource and connection string as defined in the report. Perhaps play around with the settings and different configurations for the datasource to create a different setup. The above links should be a start for some documentation.

in my case, replacing linked server connections with local (fetched from remote locations and stored in local tables)data connections helped. we also checked this for ALL subreports/linked reports and it worked fine.

This happened to me today, it was because I was using the wrong datasource in my report. So I changed the datasource manually in Report manager and it worked. I guess another choice is to redeploy your report with the correct datasource.