A separate sign in was required to connect to Outlook - MAPI Error in Office Communicator

Hello,
Recently i was able to solve AUTODISCOVER issue where free/busy information was not working in office communicator and also DG was not expanding so i published EXTERNAL URLs and it is working fine now.

Now i am facing another issue related to Outlook Integration Error. The error i am getting on communicator is

There was a problem connecting to Microsoft Office Outlook. A separate sign in was required to connect to Outlook, but the sign in dialog was canceled or closed, or your Exchange server may be unavailable. To establish the connection, sign out and then sign back in to Communicator.

When i take CONFIGURATION INFORMATION of Office Communicator, i get following results:

DG URL Internal;https://ocspool01.abc.com/GroupExpansion/Int/service.asmx;--;
DG URL External;https://ocspool01.abc.com/GroupExpansion/Ext/service.asmx;--;
Quality Metrics URI;;--;
URL Internal From Server;https://ocspool01.abc.com/Abs/Int/Handler;--;
URL External From Server;https://ocspool01.abc.com/Abs/Ext/Handler;--;
Voice mail URI;sip:htsiddiqui@abc.com;opaque=app:voicemail;--;
MRAS Server;sip:ocsedge01.abc.com@abc.com;gruu;opaque=srvr:MRAS:2nJYGHLoV0K7UsyNgoYwpwAA;Enabled;
GAL Status;https://ocspool01.abc.com/Abs/Int/Handler;--;
Controlled Phones;TRUE;--;
PC to PC AV Encryption;AV Encryption Supported;--;
Focus Factory;sip:htsiddiqui@abc.com;gruu;opaque=app:conf:focusfactory;--;
Telephony Mode;Telephony Mode UC Enabled;--;
Line;;--;
Line Configured From;Auto Line Configuration;--;
Location Profile;ocs_users_dialplan.abc.com;--;
Local Log Folder;C:\Users\Hasan\tracing;;
MAPI Information;There was a problem connecting to Microsoft Office Outlook. A separate sign in was required to connect to Outlook, but the sign in dialog was canceled or closed, or your Exchange server may be unavailable. To establish the connection, sign out and then sign back in to Communicator.;MAPI Status Error;
Inside User Status;TRUE;;
Auto Update Download Started;--;--;
Auto Update Download Completed;--;--;
Last Auto Update Request;--;--;
Pairing State;Communicator cannot connect to your desk phone because the USB cable is not plugged in. Make sure that you connect the cable.;Enabled;

So the main error is :

MAPI Information;There was a problem connecting to Microsoft Office Outlook. A separate sign in was required to connect to Outlook, but the sign in dialog was canceled or closed, or your Exchange server may be unavailable. To establish the connection, sign out and then sign back in to Communicator.;MAPI Status Error;

Now tell me what to do. I have exchange services published via TMG. But i guess there is no OCS service published via TMG. Please help which service i am require to publish via TMG. 

I am also unable to access URL https://ocspool01.abc.com/Abs/Int/Handler     it ask for password but not accepting password i have tried different users but it is not accepting passwords. and in the end it gives this error