Web Access failed after upgrade from 6.5 to 6.52

I have this strange problem.

When the server is running Domino 6.0, I can have web access to the mail files.

At that time, the changed Internet address function does not work. The address revert to the old address after a few days. Both works immediately after an address changed.

After upgrade to 6.52, I can no longer access to the mail file through the web.

Please note that during the same upgrade session, I upgrade Sametime from 3.1 to 6.51 as well.

Your suggestion is greatly appreciated.

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