Outlook Web Access does not open some messages
Outlook Web Access may have problems opening some messages. The commonality is usually that the message has a period at the end of the subject line, but it may also have other special characters in the subject line.
This problem is probably because the URLScan.DLL has been installed on the IIS Server. The URLSCAN.DLL feature was designed to help prevent directory traversal by a hostile intruder. Character sequences that are blocked include two periods ("..").
For more information on URL Scan, see KB 823175: Fine-tuning and known issues when you use the Urlscan utility in an Exchange 2003 environment If you have installed the IIS Lockdown tool on an Exchange 2000 / Windows 2000 server, then URLScan gets installed automatically.
You can allow certain URL sequences by editing the \%windir%\system32\inetsrv\urlscan\urlscan.ini file. Below is an example of the section of
.. ; Do not permit directory traversals.
./ ; Do not permit trailing dot on a directory name.
\ ; Do not permit backslashes in URL.
% ; Do not permit escaping after normalization.
& ; Do not permit multiple Common Gateway Interface processes to run on a single request.
You can comment out the character sequences that you want to allow. In order for a message with a period at the end of subject line to be opened, you must comment out the ".." line.