Nokia E51 freezes when connecting with Voxalot.
 

I have a serious problem.

My device is Nokia E51 firware version 300. It works perfectly with Voxalot on my home network, through my Linksys WRT54GL, set as Gateway (NAT).

On my work we have an AP for internet. I don`t know the exact setup but I know that we are going through NAT also, to get on the internet.

The problem is this:

1. When I try to connect with eu.voxalot.com set as Proxy, my phone freezes and restarts itself. Then it boots up and automatically tries to connect to know AP`s (to the same AP). But at the moment he tries to establish a VoIP connection with eu.voxalot.com, it restarts again. If I let it that way, it will restart all day.

2. When for a proxy I enter 85.17.19.194, it restarts again in the same fashion.

3. But when I enter free.sipout.com for proxy, it does not restart itself. It establishes a connection. The only problem is that I can call someone but nobody can call me.

4. When I set free.sipout.com and I set a STUN server with stun.voxalot.com. The phone restarts again.

It looks like some packets that are comming from Voxalot servers, are changed in some way by this AP. When packets formated in this particular way come into touch with E51, the phone freezes. It probably restarts itself as a failsafe mechanism for freezing.

What could be wrong and how can I establish a successful 2-way communication through this AP?

Upgrade the phone software.
Try to use the different STUN-server when connecting to Voxalot.
Try to disable STUN, as your NAT at work may have SIP ALG deployed.