The error message you received tends to indicate that the problem lies at the usingenglish.com end rather than at your end. But that might not necessarily be correct.
If indeed the problem lies at your end, the speed of the connection is by far the more important of the two factors mentioned by Nabadip. An old computer works fine on this site. I use several computers, ranging from a cool modern smartphone just three months old to an eight year old PC with only 512 Kb of RAM. All work fine.
So unless your computer is even more ancient and weaker than my oldest one, I think you should focus on getting a faster connection if you can.
From my point of view, there is one advertiser whose failure to respond tends to slow down usingenglish.com, namely hotchalk.com. I've no way of assessing how general or local to me this problem may be.