Problems with Exchange 2010 OWA

We have set an Exchange 2010 server’s configuration with Astaro UTM v9 following the scheme’s below:



All servers are virtual machine hosted on VMWare hypervisor

We are validating our deployment and have the following problem:
After logging to outlook web access through Astaro Firewall we’re unable to execute some features such as features in option tab (change password, create inbox rule …)
The following errors a very few times after loading the pages:



(It tries to load pages from Exchange ECP directories)

Our Firewall is configured with web application firewall enable
- Virtual and real webserver are created

When we disable WAF and use DNAT from anywhere to our client access server , we can use all OWA features .

So I think about a missing step on Astaro FW configuration and look for some suggestions to solve this issue.

Thanks for help