Paulo, sometimes an Up2Date process damages the configuration.  What happens if you restore the configuration backup made just prior to the last application of Up2Date(s)?

If that doesn't solve the problem, try creating a new Virtual Server with new Firewall Profile and new Real Server that duplicate what you have.

Any luck with either of those?

Cheers - Bob

Thanks BAlfson for the suggestion. Tried both of them with no success. I have passed this to support with no reply at the moment.

Meanwhile the customer is using VPN's from all the devices they want to access email.

I am suspecting of some kind of incompatibility between IIS in 2003 and the new WAF.

Thanks Paulo

Hi Paulo,

having the same problem with 2003. Did support advance you with the reason about this?

Contacted support.

 The problem is related to the cyphers used in IIS of the legacy OS. You have to a) Upgrade OS or b) Downgrade UTM version.

--EDIT-----

from support:

 "The reason the behaviour is occurring is that UTM v9.5 no longer supports the RC4 Cipher with TLS 1.0 as it is deprecated and has been removed from WAF.

We still support TLS 1.0 but no longer support the RC4 cipher."

I could fix this with

https://www.nartac.com/Products/IISCrypto

Run the "Best Practive" config