All Downloads are Stalled, what is causing this?

[Soundman192]

Ok, so I moved over from uTorrent because after 5000 torrents, uTorrent starts failing.  I have been using qBt for a month or so, but now any torrent I try to download from any site, moves data for 10-20 secs then falls into a "Stalled" mode.  I paused all 5700 torrents so my downloads are the only thing active, yet my download speed is 0 B/s and all stalled.  I can tweek them, ie pause/resume and I get some traffic for a few seconds then back to "Stalled".  Something is definately wrong with qBt.  I'm running 4.1.4.

As I have been doing this for years with uTorrent, I do not suspect my network in anyway.  It is something in the way qBt works internally.  Does anyone have an idea on what I need to do get this working?  I'm not using Torrent Queueing, but would like to once it gets fixed. 

Hopefully there is a qBt guru out there that knows what's happening.

Thanks in advance for any help

UPDATE: (1-7-2019)

I figured out the stalling was due to and out of space condition on one of my volumes.  I have 5 large volumes so easy to miss.  qBt does not really tell you this is the issue.  Once I moved some torrents around, things cleared up, just wish qBt was more informative that a file it is trying to write to failed due to a space condition vs just going into a "Stalled" state. So this issue is resolved.  Now I have a moving file issue see below.

[Switeck]

Neither uTorrent nor qBitTorrent may be written to handle 5000+ torrents together at once.
Just keeping the GUI list of torrents sorted and refreshed may be a small cpu load.

[Brambles]

Same for me...

[Cholliwog]

If you're on a vpn, try resetting your connection, and if necessary, your modem/router.
Make sure you didn't fiddle with allowed connections limits. Or setting upload speed to 1kbps. In other words, try deleting the settings file and seeing if it helps.
Make sure it's not firewalled.

[there]

make sure your disk is not full too