RHEL is a supported OS to install on Hyper-V. First, please confirm you are running a supported version as per https://learn.microsoft.com/en-us/windows-server/virtualization/hyper-v/supported-centos-and-red-hat-enterprise-linux-virtual-machines-on-hyper-v.
Another thing you may want to check out is the best practices page here - https://learn.microsoft.com/en-us/windows-server/virtualization/hyper-v/best-practices-for-running-linux-on-hyper-v
Beyond this, is there any specific error you are getting?
Thanks,
Trent