I have an Image Service with WMS capability enabled, published to ArcGIS Server 10.2 on Windows Server 2012 R2. The image service publishes fine and I can access it through ArcMap. When I try to access the WMS, I get errors. If I try the GetCapabilities request, it returns error 400 - The request sent by the client was syntactically incorrect.
If I try to add the WMS server to ArcMap, when I click on Get Layers it returns a connection error - "An event was unable to invoke any of the subscribers"
I have previously published image services with WMS that work fine, but can't work out why this one doesn't.