We are trying to integrate Ninja Forms with Dropbox. When we select allow on: "Ninja Forms Uploads would like access to its own folder, Apps › Ninja Forms Uploads, inside your Dropbox. Learn more" we receive the following error message:
This site can’t be reached
oauth.polevaultweb.com’s server IP address could not be found.
After the user authorizes on app on Dropbox like this, Dropbox sends the user back to the address specified by the app. In this case, that address is on oauth.polevaultweb.com. This hostname 'oauth.polevaultweb.com' doesn't seem to be registered in DNS, so your browser can't find it. (I also just checked and can confirm it doesn't appear to be registered when I try looking it up.)
This isn't something under Dropbox's control though. If this isn't the hostname you meant to use, you should replace it with the correct one. If this is the hostname you meant to use, you'll need to register it in the DNS system.