User login fails with invalid credentials due to incorrect identity source configuration

Products

• VMware vCenter Server

Issue/Introduction

When attempting to log in to the environment, users may encounter the error message:
`Invalid Credentials`
This occurs even when the provided password is correct. 
The issue is typically observed during the authentication phase and is rooted in the identity source failing to correctly locate or bind to the user objects in the directory service.

Environment

 VMware vCenter Server
 Active Directory Identity Source

Cause

The identity source configuration contains an incorrect Base Distinguished Name (DN) or an improperly formatted Bind Username. 
If the Base DN points to an Organizational Unit (OU) that does not contain the users, or if there are syntax errors in the DN string (e.g., using hyphens instead of equals signs), the search will fail.

Resolution

To resolve this issue, update the identity source settings with the correct directory paths and user formats:

1.  Log in to the management console with administrative privileges.
2.  Navigate to the Identity Source configuration section.
3.  Locate the affected Active Directory source and select Edit.
4.  Update the Base distinguished name for users to point to the correct OU. 
       Example: `OU=Admin,OU=<domain>,DC=<domain>,DC=LOCAL`
5.  Change the Username (Bind account) from a full Distinguished Name to the User Principal Name (UPN) format.
       Example: `svc-vcenter@<domain>.local`
6.  Click Save or OK.
7.  Verify that the user can now log in successfully.