Either the User, abc does not have access to the xyz Database, or the database does not exist.

Either the User, abc does not have access to the xyz Database, or the database does not exist.

Issue:Either the User, abc does not have access to the xyz Database, or the database does not exist.\

Issue Description:While Refreshing an Excel report which was connected to analysis service Data cube showing the Below error
Either the User, abc does not have access to the xyz Database, or the database does not exist.

Check -Login to Analysis Service with the user who is facing issue while viewing Report in SP Site
IF the user is not able to see any Database after connecting to analysis server that means the User doesn't have permission to access Database  as in below screenshot.

Solution-Login to analysis services with your Master user or system user in most case which is Sa.
Expand Analysis Service Database
Role
--XXXOlapdataRole
--Rightclick
--Properties
--Membership
--Add the above user who was facing issue 
--ok
Screenshot Below.

Preview the Report by login with the User facing Issue refresh the Report -It will Refresh the Report without any Issue.

NOTE: If after entering the user name you are still not getting the User Go to location and Select all Directory as below screenshot.