Synch Notes & Internet Password failing in ADMINP

I have a Domino server that has a Security Policy in place that synchs the Notes client password with the Internet password. We have HTTP Session Authentication enabled and synch appears to be configured properly but when we check ADMIN4.NSF, we see the following error

Title: Acme’s Directory File name: Server1/Acme!!names.nsf; Error: The server is not responding. The server may be down or you may be experiencing network problems. Contact your system administrator if this problem persists.

There are other admin requests that reference names.nsf and they appear to be working fine.

Could this be an issue with the Notes client notes.ini file?

Thanks…