ApiError: Not Found at Object.parseHttpRespBody@google-cloud/storage/

Im trying to list files from a folder from Firebase Storage via functions.

`"@google-cloud/storage": "^1.6.0",`

`ApiError: Not Found
at Object.parseHttpRespBody (/user_code/node_modules/@google-cloud/storage/node_modules/@google-cloud/common/src/util.js`

### How to reproduce these conditions
When I make a POST request to : `https://us-central1-.cloudfunctions.net/listFiles`
with post data {"uid": "SOME_LONG_STRING"}

### I get following error in postman
```
{"code":404,"errors":[{"domain":"global","reason":"notFound","message":"Not Found"}],"message":"Not Found"}
```

### Firebase LOG:

{ ApiError: Not Found
at Object.parseHttpRespBody (/user_code/node_modules/@google-cloud/storage/node_modules/@google-cloud/common/src/util.js:199:30)
at Object.handleResp (/user_code/node_modules/@google-cloud/storage/node_modules/@google-cloud/common/src/util.js:137:18)
at /user_code/node_modules/@google-cloud/storage/node_modules/@google-cloud/common/src/util.js:502:12
at Request.onResponse [as _callback] (/user_code/node_modules/@google-cloud/storage/node_modules/retry-request/index.js:195:7)
at Request.self.callback (/user_code/node_modules/@google-cloud/storage/node_modules/request/request.js:186:22)
at emitTwo (events.js:106:13)
at Request.emit (events.js:191:7)
at Request. (/user_code/node_modules/@google-cloud/storage/node_modules/request/request.js:1163:10)
at emitOne (events.js:96:13)
at Request.emit (events.js:188:7)
code: 404,
errors: [ { domain: 'global', reason: 'notFound', message: 'Not Found' } ],
response: undefined,
message: 'Not Found' }

## FUNCTIONS code
[code](https://gist.github.com/steelx/ba31b18f090faa10a6a135804539b80f)

https://gist.github.com/steelx/ba31b18f090faa10a6a135804539b80f