Unable to use TortoiseSVN to checkout from http://svn.reactos.org

I just reloaded the whole system today and installed the latest TortoiseSVN(I didn't bother to update it before). Suddenly I can't checkout the code. The error code is "408 Request Timeout".

On the other hand, I can use svn://svn.reactos.org/reactos/trunk/reactos, so the cause of the problem must be the url I use: http://svn.reactos.org/reactos/trunk/reactos. Since my school network allows 80 & 443 ports only and SVN protocol uses 3690, I have no choice.

I can go to http://svn.reactos.org/reactos/trunk/reactos using my web browser. So the connection is fine. Maybe there is an incompatibility between the svn server and the client.