VPN connected in my laptop but cant office desktop thro RDP

Hello,

I connected to VPN in my laptop (in home network) and i tried accessing
my office computer thro Remote desktop conn. But it gives error.

REMOTE DESKTOP CANT FIND THE COMPUTER.............
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also i pinged the office computer IP from laptop, but timed out.
But my colleague can connect to my office desktop thro this personal laptop from his home

please help on this.