Sadly, no magic there as your file name is too long and you need to shorten it.
Did you find a sweet spot for your *arr renaming scheme ? 
I meant your sonarr renaming scheme, if you're OK to share it
Sure:
I follow some of the stuff here -> Recommended naming scheme - TRaSH Guides (trash-guides.info)
But those names are too long for my taste as I don't care about some of the details they have, but generally gives a good idea and why.
OK, well I had complex naming scheme, but I'll go back to something simple 
Thanks you.
Also, as GDrive, Dropbox require plex autoscan, right ?
I didn’t use it for either.
Then are you just running full scan via the Scheduled Plex Tasks ?
EDIT : I'm trying something - I might have done something wrong
Well, as I said this is working, but it looks like that I always have to renew my token
Failed to create file system for "dbuploadcrypt:": failed to make remote "dbupload:/Chiffrement" to wrap: get current account failed: Post "https://api.dropboxapi.com/2/users/get_current_account": couldn't fetch token - maybe it has expired? - refresh with "rclone config reconnect dbupload:": oauth2: cannot fetch token: 400 Bad Request
Response: {"error": "invalid_grant", "error_description": "refresh token is invalid or revoked"}
Perhaps I did something wrong,
I use Sonarr/Radarr connected with Plex to trigger scans when they add things.
Possibly. You'd have to share all your steps / screenshots of what you did as I can't see your screen.
But is a partial scan (as autoscan) ?
It's working for now, I'll see if I managed to solve the problem or not
I really don't care what type of scan it is. I just let the system do its thing.
Well, it was kind of a problem on GDrive (because of the API limitation).
On Dropbox, do you know the app limits in terms of API calls ?
Yesterday, I had 56 500 API calls on my first app and 25 000 on the second.
There's no API limitation in Google that impacts that.
Unlimited.
I think I've been 24 hours API banned on my GDrive a year ago, because I tried to scan my library from scratch.
Then, if it's unlimited, why are you using 2 apps on Dropbox? Perhaps we misunderstood each other 
.
You don't get banned on Google. You hit a download quota more related to your setup than anything else.
Any provider may have unlimited API hits but every provider has rate limiting. I use two apps so I can spread the load between them.
Hmm, OK, right, I'm downloading series on scan in order to detect and skip the intros.
So by that, you mean that on a month for example, there is no real limitation on Dropbox, but we must not exceed X calls by seconds ?
Yes, that's correct.
There isn't an exact post on the rate limiting generally from any provider as they don't share specifics other than they have a rate limiting policy and avoid it.
Generally, folks feel that 12 TPS per second for dropbox per app seems to be a sweet spot.
All right, thanks you!
Is 12 tps better than GDrive? 
I don't use Google Drive so I really don't know.
Rate limits are per provider and not really a 'better' thing than another.