After logging into EEM as EiamAdmin, we navigate to: "Manage Identities" -> Users
Then we search for a user which returns the following: "EE_POZERROR Repository Error ISE_BACKENDDOWN backend is down"
Release : 4.3
Component : Process Automation
This article applies when the error above is seen while navigating to "Configure" -> "User Store" -> "User Store" shows a Status with a Red X - and hovering the mouse over the Red X icon shows "Bind failed". If the error in the description is seen and this "User Store" screen does not show a connection to AD/LDAP, or the AD/LDAP connection is successful then this article/solution does not apply.
To resolve the issue:
After going through the steps above the AD/LDAP connection should show it is connecting successfully (with an icon showing a white checkmark in a green circle in the Status field).
Examine the EEM itechpoz_warn_20XXXXXX.log. An entry may appear such as this sample
 20XXXXXX.024304.712 WARN : TLS/SSL handshake failed for call from 188.8.131.52:46622
This indicates the problem may be the network or firewall blocking the given IP Address/port combination