Does the system administrator need to install anything extra to get EWS Managed API working for clients on Exchange 2010? At the moment I am getting problems just using AutoDiscover via the managed API so I'm beginning to think the server has been configured incorrectly.
Has any administrator here had any experience with setting up Exchange 2010 to allow access via EWS Managed API?
EWS is enabled by default in Exchange 2010 with no changes needed. It can be affected by common changes made to the system after installation. Installing an SSL certificate with a different name than the server's can cause problems. ie: using mail.company.com instead of exmail01.company.com.
You can use the Exchange Powershell command Set-AutodiscoverVirtualDirectory to change the Internal and External URLs used to connect to EWS/Autodiscovery.
The Test-OutlookWebServices command will run through a series of tests and let you know what failed.
From there, you will be able to see the specific errors in your Autodiscovery configuration. Once they are fixed, you should see the Managed EWS API work correctly.