PDA application goes offline

Hi All,

I have a PDA application which continuously pings a web servcie on the
remote server to check if the connectivity still exists. For sometime,
the application is able to ping the web service. But at certain point
of time, the application is not able to ping the web service. After
this, the connectivity is lost to the web service. An HTTP: 401
Unauthorized exception is thrown even though the credentials are always
assigned to the http headers. Even after the connectivity is lost, the
PDA is still able to browse other sites from Pocket IE.

Could anyone please help me on this?

Thanks,
Kshama