refresh token

Greetings everyone just gonna copy and paste this here the letters in blue is where im having issues the output i will put in red can someone please help :

 

**Configure your Dropbox application**

- Create a Dropbox account.
- [Create a Dropbox "App"](https://www.dropbox.com/developers/apps/create) with a "Scoped access" API and a "Full Dropbox" acces> - Go to the settings of this app and write down your "App key" and "App secret".
*These are your "<APP_KEY>" and "<APP_SECRET>".*
- Next, go to the "Permissions" tab and enable the "files.metadata.write" and "files.content.write" permissions.
- After that, open this link in your browser *(values between brackets must be changed)*.
```
https://www.dropbox.com/oauth2/authorize?client_id=<APP_KEY>&token_access_type=offline&response_type=code
```
- Connect your application, allow its permissions, and note the code it gives you.
*This is your "<APP_CODE>".*
- Open a command prompt and run this command *(values between brackets must be changed)*.
```
curl https://api.dropbox.com/oauth2/token -d code=<APP_CODE> -d grant_type=authorization_code -u <APP_KEY>:<APP_SECRET>
```
- Note the "refresh_token" value of the result.
*This is your "<REFRESH_TOKEN>".*

 

Invoke-WebRequest : Parameter cannot be processed because the parameter name 'u' is ambiguous. Possible matches include:
-UseBasicParsing -Uri -UseDefaultCredentials -UserAgent.
At line:1 char:129
+ ... AAFZweC4ck6XN_KBdSolmpzkI -d grant_type=authorization_code -u 5u3fux9 ...

or:

curl: (35) Recv failure: Connection reset by peer