access of WML site through cell phone seems flakey

I just started a new subdomain on hosting rails. I launched it a
couple of days ago. It is a site that
can render onto mobile devices using WAP/WML or through a regular
browser.

It seems flaky with the mobile cell phone access, because sometimes
it works and sometimes it stops working for several hours and then it
seems like it's fine again, with a regular browser it seems ok, though
yesterday that had been flaky as well. I have a different subdomain
that I have been using with mobile interface that has been working
fine for a year.

When it stops working, I don't think the cell service is actually
accessing the site because I see no request in the log file, and the
cell phone goes into a google search mode for the url.

Is it possible that the dns server is messed up somehow or it takes a
long time to propagate and it is switching to different servers ?

If there are any suggestion on what I could try, please let me know.

now what I am seeing is sometimes the mobile browser says it can't
display the page, in those cases I can definitely see that the request
made it to the server as the log file has the request.

Other times it says: proxy server recv invalid response from upstream
server. reason: dns lookup failure

From experience, it seems like if I wait 6 hours or so, it may clear
up, though I find it very strange.