Cannot start ipfs webUI

I cannot open the ipfs webui…
I’m using GCP, vm-instance
Ubuntu 16.04

$ ipfs daemon
Initializing daemon…
go-ipfs version: 0.5.0
Repo version: 9
System version: amd64/linux
Golang version: go1.13.10
API server listening on /ip4/127.0.0.1/tcp/5001
WebUI: [http://127.0.0.1:5001/webui] --> 400 error
Gateway (readonly) server listening on /ip4/127.0.0.1/tcp/8080
Daemon is ready