What causes uTorrent "Error 10061" peer errors?

[SumGuy7]

I've been using uTorrent 1.8.5 for years and in general I have no problems downloading stuff with it.

But something that I've seen for quite a while is that for some torrents where I might be the only seed, and where it appears that there are a handful of peers - none of them connect to me to download. Or perhaps 1 or 2 will connect to me but the others don't.

For example, right now I'm seeding 9 torrents. For one of them, there are 2 seeds listed, and 8 peers. I'm uploading to only 1 peer (at 50 kb/sec). For the other 8 torrents, there are from 1 to 8 seeds listed for them, and anywhere from 1 to 40 peers - and none of those peers are downloading from me. For 4 of them, there's only 1 seed listed (presumably - me!) and anywhere from 1 to 18 peers - and none of them are connecting to me.

DHT, Peer Exchange and Local Peer Discovery is enabled for all 9 torrents. At the bottom of the uTorrent window it says "DHT: 345 nodes".

When I look at the logs, I see lots of these:

1.2.3.4 Connecting: source: TH

1.2.3.4 Disconnect: Peer error: Error 10061

1.2.3.4 Connecting: source: TH

1.2.3.4 Connecting: source: TH

2.3.4.5: Connecting: source H

2.3.4.5: Disconnect: Connection closed

3.4.5.6: Disconnect: Peer error: offline (time out)

In the Trackers tab, I've removed all the trackers that give errors (many of these errors are also 10061) so that I'm down to about 6 or 7 working trackers for each torrent (along with DHT, Local Peer Discovery, and Peer Exchange - which are all working).

So what exactly does this "10061" mean, and why are the peers for these some-what rare torrents that I'm seeding not wanting (or having problems) connecting to me?