Assigning multiple variable in Assign message policy

[anarjinary]

I am trying to populate the 'endpoint' variable as below using assign message policy.

Trial A seems to work as expected. - I ran this request to test if the variable {url_deviceInfo} is getting populted or not.

Whereas TrialB throws an error - service unavailable.

Please let me know how to make Trial B work, {url_deviceInfo} is getting populated from KVM.

{url_deviceInfo} contains the hostname:port (eg: xyz.com:1234)

Trial A

<AssignVariable>
        <Name>endpoint2</Name>
        <Value>http://xyz.com/infinity/v1/subscriptions/{url_deviceInfo}/{req.partnerId}/</Value>
    </AssignVariable>

Trial B

<AssignVariable>
        <Name>endpoint2</Name>
        <Value>http://{url_deviceInfo}/infinity/v1/subscriptions/{req.partnerId}/</Value>
    </AssignVariable>