SharePoint: People Picker error: “user does not exist or is not unique” – similar account names
Consider the following scenario: SharePoint 2013 or 2016 servers are in the contoso.com domain contoso.com has a trust relationship with the corp.fabrikam.com domain. The peoplepicker-searchadforests property is configured like this: “forest:contoso.com;forest:corp.fabrikam.com,corp\SPadmin,*****“ You use People Picker to find a user. If the users account name (samAccountName) is unique, you have no issues adding it to SharePoint.