OWA Send Message Gives Forbidden Message

This happens when the directory permissions are incorrect in IIS, the quickest way to reset them is as follows:-owa forbidden sending

In the Exchange System Manager Console, expanded: servers/protocols/http . Then right click the “exchange” virtual directory and choose properties. Click the access tab at the top and then uncheck directory browsing.
Click apply and OK. Then go back and re-check the directory browsing box. Apply and OK and it should work.