Cannot send IM from Outlook Web Apps

There are three possible reasons why you can't send IM from Outlook Web Apps (OWA).
I assume first, the integration was done according to the recommendations given. Meaning you have also tested that internal IM from OWA was possible to send and receive.

If you encounter the following behavior:
- Presence can be queried, but I’M cannot be initiated.
- If you receive an external IM, you are able to answer the external contact.
- You cannot receive or send external IM from OWA
While you are using the OCSLogger on the Lync Edge Server, you might see the following SIP 403 Forbidden message:
Text: SUBSCRIBE request for get rich presence was rejected by the Access Edge Server

You also see the internal Exchange Server with ipconfig -displaydns as:

1. Your external policy do not allow access to federated partner or public IM systems. Therefore you need to change those policies, or assign the correct policy to the affected users

2. You have the correct policy, but you sill can't reach out to external contact, the SIP address might be incorrect, or the federated partner is not allowed to communicated externally

3. Most likely, if the policy settings are correct the third possibility occurs. For external IM communication you must have a CONTACT OBJECT in Exchange. IM can only be initiated via a contact object and this is different from your Lync Client, where you are able to type a address in the address bar.
In OWA you can add a contact including the CHAT address, but here you have to add the chat address in the following format:
OWA can only initiate a IM if the SIP Prefix is present, else the error message shown above will be logged. This is an issue by design of Exchange utilizing the UCMA API.
Additionally, you also have to apply the Lync Cumulative Updates to the UCMA installed on each Exchange CAS Server. This is mostly forgotten by the Exchange admins.

This article says, if you wish to communicate with external buddies, you have to add a Outlook Contact and MUST include SIP: prefix.


  1. I was getting the Outlook error primarily. It was basically the outlook loading profile stuck. Can anybody please tell me how to fix it?

    1. Hi John, where exactly you got this error? if its the issue describe in the article, you only need to follow the steps provided. This issue was only with OCS and Lync, not with SfB. You can use the contact button and get in touch with me directly.


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