Different size of disk in disk management and my computer, after extend in Hyper-V

I have a problem after live extend disk from Hyper-V on running machine.

I normally increase the disk size from Hyper-V (300GB->1.3TB), then on system using disk management for extend.

In this case, disk management size displayed is accurate (1.3 TB), but when viewing my computer explorer, disk is still 300 GB.

I was using diskpart and extend filesystem but doesn't work. Server was restarted too. Any ideas? It's WS 2019.