SOLUTION: HTTP 405 Error. Lync Client EWS Not Enabled. No meeting Icon on Lync Client

Applies to Exchange 2010 and Lync 2013 Desktop Client

All Exchange autodiscovery settings are OK. (Exchange 2010 Autodiscover virtual directory settings, DNS, SSL certificate on CAS server, SANs for etc). But you still cannot see conversation  history in  Lync 2013 Desktop . Also cannot see meeting icon in Lync 2013 Desktop client. (those features available via Exchange Web Services)

Also If you check Lync Client configuration (ctrl+right click lync icon on notification area + Configuration Information) you noticed that EWS status is not OK and EWS Internal URL and EWS External URL values are empty.

In Exchange CAS Server IIS logs:
If Lync 2013 Client  exits and signs in you see that client first access (by GET method) /autodiscover/autodiscover.xml
but then you got the following:

14-07-18 07:05:05 POST /autodiscover/autodiscover.svc – 443 – OC/15.0.4551.1005+(Microsoft+Lync) 405 0 64 0

HTPP 405 error code means Method not allowed. It is clear that client cannot POST data using autodiscover.svc file.

Missing handler mapping *.svc in IIS on Exchange 2010 CAS Server that is pointed by

Resolution 1:
1-On Exchange 2010 CAS Server start IIS Management console
2-select Autodiscover virtual directory and double click Handler Mappings.
You see that svc-Integrated *.svc entry is missing
3- click add manged Handler and enter:

Requested Path:

System.ServiceModel.Activation.HttpHandler, System.ServiceModel, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089

Leave the request Restrictions default. (I just copied this handler from another correctly working Exchange 2010 CAS Server.


4-Click OK. and run IISreset
5-Exit and sign in Lync 2013 client now you should see Meeting icon and Conversation History. Also you can see EWS Internal URL and EWS External URL values are now points to CAS servers. (You may need to wait for 10-20 seconds)

Resolution 2:
An alternative solution is to add the following entry in C:\Windows\system32\inetsrv\config\applicationHost.config file and run IIS reset

<add name=”svc-Integrated” path=”*.svc” verb=”*” type=”System.ServiceModel.Activation.HttpHandler, System.ServiceModel, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089″ preCondition=”integratedMode” />

then Exit and sign in Lync 2013 client

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