Synchronization blocked on "waiting to download"

Hi every body,
I have a NAS but due to a not enough powerful problem, I want to change. In waiting to buy a new one, I installed PMS on my mac and put all files in an external drive disc. B)
The problem is that when I want to synchronize movies or tv show on iPad/iPhone, it works from the NAS but it takes a looooooong time cause of the conversion, and if I do the synchronization from my mac the conversion is very very fast but all files are pending on “waiting to be downloaded” on the iPad/iPhone and nothing happens …

I tried to found something similar on the forum but I didn’t find any solution. :’(

Do you have an idea ?

Thanks all

Anyone ? :’(
A little up …

Sorry. Not enough info to diagnose. Are you setting up the sync from Plex Web or your device? How many items are you trying to sync and do you have enough storage space on both your server and on your device? If you can recreate a sync job then provide both the PMS and app logs, that would help.

Hey,
I have enough Storage on both server and device. At the beginning I tried to sync a full season. It failed then I tried just with one episode. It failed too. I tried both way to sync, from device (iPad or iPhone) and from Plex Web. It failed too … It’s very strange because when I want to sync from my NAS, it works but it’s very very very long (My NAS is so weak to convert quickly file) …
I will provide you logs when I come back at home
Thank you