Could not logon to directory

What causes this issue?

The combination of user name (DN) and password transferred to the
directory was not accepted by the directory.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the set or entered data for the user and password for the
directory.
If you are using an application with which you do not need to enter
this data directly, you can find the data as configuration setting in
the LDAP server used ("System User" field).

Procedure for System Administrators

Check whether you can log on to the directory with the entered data
using the LDAP protocol.
Note: A frequent error when using the Microsoft Active Directory is
that the user enters their Microsoft Windows user name instead of
the full Distinguished Name, since it is also possible to log on to
the directory using this Microsoft Windows logon with Microsoft tools
(such as ldp.exe). However, these tools do not use the user/password
logon used by the SAP system.

Error message extract from SAP system. Copyright SAP SE.