qBittorrent official forums

I just signed up to ExpressVPN 2 days ago for their split tunneling so I can leave the browser and programs connecting via ISP and only encrypt torrent traffic.

I've since had this issue with DHT dying and trackers not responding two times now and don't know what to do. I have qBittorrent connecting only via the ExpressVPN interface in Advanced options. Woke PC from sleep this morning and qBit couldn't function, restarted qBit and it was all ok until it happened again later in the evening, so I restarted the app again and then it connects. The PC was on all day

I am not with them, and do not know this service, but I would try different exit countries that the ones you have chosen.

you could to test, disable the vpn software, share nothing, have  nothing incriminating queued, the download a few linux distros?

Think your next point of call is the vpn provider