Action URL "incoming call"

Hello
I want to display customer information based on the callers number when a call is coming in. My script already works for Aastra and Snom phones. I can see that the T46G is calling the script and in pcap log I can see that the xml is delivered to the phone.

Test XML Code:
<?xml version="1.0"?><YealinkIPPhoneFormattedTextScreen doneAction="http://10.1.0.105/menu.php" Beep="yes" Timeout="60" LockIn="yes"><Scroll><Line Size="normal">Current Conditions</Line><Line Size="small">Temperature: 2.1°C</Line><Line Size="small">Pressure: 100.7 kPa falling</Line><Line Size="small">Wind: S 31 km/h gust 45 km/h</Line><Line Size="normal">Monday, 13 January Forecast</Line><Line Size="small">Cloudy. A few showers beginning near noon.</Line><Line Size="small">Wind southwest 30 km/h. High plus 4.</Line></Scroll></YealinkIPPhoneFormattedTextScreen>

But it's not shown on the phone.

Do you have an idea how I can get it to work?

Thanks
Michael