@DIVAKAR Good day,
Here is the latest firmware of RE450 V3, please make sure the firmware on RE is up to date:
https://www.tp-link.com/support/download/re450/v3/
During the setup of the extender, did you see 5Ghz Wi-Fi signal from Huawei Router? If RE450 does not find 5Ghz signal, please check suggestion mentioned in this FAQ:
If RE was able to detect router's 5Ghz signal but failed to connect to that 5Ghz, would you please help us check the 5Ghz WIFI password on your cell phone?
Go to Settings-> WiFi on your phone, Tap (or Long press the router's WiFi name ->Forget / Delete the network
Please reconnect to your router 5Ghz wifi and it will ask for a password, will it accept your router password?