Check the epoapsvr.log or the orion.log; test your LDAP connection through "registered servers" - if it fails registering LDAP or setting up/launch an AD Sync Task and check the epoapsvr.log or the orion.log.
check basic network connectivity between your ldap servers and epo. also make sure the account that you are using is not disabled.
We appear to be experiencing some very strange problems...
The bottom task has been disabled and deleted, It is running a query to deploy new agents via a query. I have deleted yet it still appears in the server task log ONLY under in progress. We have already managed to get the CCC Active Directory Sync working yesterday but terminating this task and restarting the EPO services. But I've come in today and again the sync is being held up by this unwanted task. It seems to be stuck on the back end somewhere, and even though the task has been terminated yesterday, it still appears again today with 139 hours on the running time.
Any ideas? Its a strange one...
This may help:
Server task configured to execute Run Client Task Now task may run indefinitely or get stuck "In Progress" Technical Articles ID: KB85013
Even thou "...CCC Active Directory Sync working yesterday but terminating this task and restarting the EPO services..." you may need to stop/start the services again or schedule a reboot.
This is just FYI.
As tao mentioned earlier, you can restart all three ePO services (OR reboot ePO server) to clear out all the "in-progress" tasks. That works, but a graceful solution would be nice without restarting services/server.
If anyone is interested,
Determine hung/"In-Progress" ePO tasks in sql server. Run the following against ePO database in sql:
SELECT [Id], [Name], [StartDate], [EndDate], [UserName], [ParentId], [Status]
Where Status = 10
This Query will select all the hung tasks. Status 0 is successful, 1 is failed and 10 is hung tasks with NULL values in "EndDate" colum.