Error on setting Instance IP address

Hi, all.

I have a problem setting Instance IP address of Azure Virtual Machine.

Given the virtual machine, restored from backup in Classic portal.

Some changes, like changing size and security group where successfully applied to this machine and it was restarted after these changes. 

So, the problem: In new Portal I select the virtual machine -> IP Addresses -> Instance IP address, then change the setting from OFF to ON and click Save. As a result I get the following error:Failed to update IP address in the virtual machine 'abir2'. Error: The operation '499cc66c7427008281574c204a8ee3d6' failed: 'The server encountered an internal error. Please retry the request.'.

What could be the problem and how to solve it?

Please, advise.

Thanks.