Probably not the case of everybody but I had the same problem. I was using the last, in my case, the error was because I was using jfrog manage from the company where I am working.
npm config list
The result was
; cli configs
metrics-registry = "https://COMPANYNAME.jfrog.io/COMPANYNAM/api/npm/npm/"
scope = ""
user-agent = "npm/6.3.0 node/v8.11.2 win32 x64"
; userconfig C:\Users\USER\.npmrc
always-auth = true
email = "XXXXXXXXX"
registry = "https://COMPANYNAME.jfrog.io/COMPANYNAME/api/npm/npm/"
; builtin config undefined
prefix = "C:\\Users\\XXXXX\\AppData\\Roaming\\npm"
; node bin location = C:\Program Files\nodejs\node.exe
; cwd = C:\WINDOWS\system32
; HOME = C:\Users\XXXXXX
; "npm config ls -l" to show all defaults.
I solve the problem by using the global metrics.