@Florin Thanks for raising this question! Firstly, apologies for the delay in responding here and any inconvenience this issue may have caused. Kindly try the following steps to isolate the issue: If you deploy your cluster using an ARM template you can specify the Pod CIDR value using the podCidr property of the networkProfile ContainerServiceNetworkProfile object For now it's not possible to set that value through Azure Portal.
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Also, I see you have posted similar query in SO forum, If you still have any question I will be happy to assist you and work closer on this issue.
Hope this helps!
Kindly let us know if the above helps or you need further assistance on this issue.
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