In my case, peers would barely connect after download, even with no downloads at all.
But one of devs replied to my thread and suggested for me to open a range of ports for deluge, this helped.
So it seems as a restriction on the connections per port.

Hey its seems this improved peer connectivity a lot, can you explain why? I've opened 10 ports which was easy to do in another router. Now I'm back at home and using a different router "nano station lovo M5" which is my ISP choice. Problem is it doesn't seem to be able to open a range of p...

Leave the outgoing ports as random and set a range of incoming ports (~5). You should really be using the latest version of deluge. Thanks, finally someone from the project who gives a peep. Well, I'm using current Debian testing version. Just checked and its a couple of years behind on the release...

Make sure you have ports forwarded on your router for the incoming ports. Not trying to be mean or anything but, if you had read the thread you would know I did open ports. But still just in case... here is how I did it: One port only both for incoming and outgoing connections, didn't forward more ...

I can relate to this, peers connects and data is uploaded but at a very lower rate when compared to others clients. Its true sometimes peer connects and slowly sends data, but its only a couple of peers ( out of 20 available slots) in a couple of torrents( out of 8 for upload) that gets connected. I...

Package version, just in case:

Hey folks, hello to you all and thanks for the developers of this wonderful advanced torrent application. I guess I'm having a issue, since my upload speed is way lower than what it used to be with Transmission. I've tried searching about this, and normally it would point to outdated libtorrent pack...