Plex media ===> DropBox App sharing folder issue(s)

[#1]

I have recently installed the DropBox App (as an nagging request from  SWMBO) via the UNSUPPORTED apps section Via Plex Media server & am having trouble getting it to work for sharing any single files yet alone any folders
It asks for a Token (which I understand is to be the Shared Link)

However no matter what I do I always get
Configuration ERROR! popping up for a split second & unable to grab a screenshot
That said I managed to get a photo, not best quality I know however time was not on my side

All I get from the App side is Settings page(s)
1^st Page

2^nd Page 1^st half of the menu


2^nd Page 2^nd half of the menu

The main questions I can think of atm
1. Is this an issue with the App, Network, Dropbox, other
2. Is this a router setting / issue related
3. Is this PN related (Highly unlikely)
4. What if anything am I inadvertently overlooking
5. Does this App actually work
6. Do I need to sign up for a Plex pass to get this to work

[#2]

Dropbox uses a UDP protocol to check things are OK - every few seconds.
Google "port 17500"

[#3]

DB, works well on the desktop app that is installed to sync with all other devices, including their web portal.
Are you saying I may have to make changes to the router ?
According to DB forum
The Lan Sync is already ticked

[#4]

Could this be the reason(s) why I can not get the installable app to work
[quote= https://forums.plex.tv/index.php/topic/100386-rel-dropbox/]What else is important to know?
Plex cannot transcode streams and urls (right now). So you have to make sure that the videocontent can be played on your plex devices. H264 as the video codec and AAC as the audio codec will be a good choice.
Where can I download the latest release of this channel?
It's located at github: https://github.com/r.../Dropbox.bundle
[quote= https://github.com/realriot/Dropbox.bundle]Dropbox for Plex is a browser channel which enables you to watch and hear your media directly from the cloud.
Please keep in mind that this channel will not transcode any content. So you have to make sure that the content is viewable on your devices. If Plex will support any transcoding of streamed content in the future, this feature can be implemented afterwards.
Your decision
This channels supports the dropbox and sandbox mode from dropbox. The mode differs from what this channel can access in your dropbox. dropbox mode is the god mode which enables this channel to see all your files. If you'd like to jail this channel to a special folder, you have to use the sandbox mode. You have to come to a decision when you'll create an app within your own dropbox developer console.
Authorize access
Select the access mode and get the access token for your Dropbox account at: http://api.schmidt.ps/authDropboxChannel4Plex
After validation an access token is displayed which you have to enter within the channel preferences.
Please secure you access token. NOBODY may know it! This token allows full access to your configured dropbox space.
[quote= http://gizmodo.com/5974438/]Media streaming software Plex now lets you turn your server off and stream content from Dropbox instead. Neat.

Quote

"and will be available to paying users of the PlexPass subscription service later this month"