After applying August 2026 Windows Updates, EPG Web Management shows "The resource cannot be found"

After applying August 2026 Windows Updates, EPG Web Management shows "The resource cannot be found"

This article applies to the following products:

• Messageware Exchange Protocol Guard 2019
• Messageware Exchange Protocol Guard 2016
• Messageware Exchange Protocol Guard 2013

SYMPTOM

During opening EPG Admin, EPG Reports, or EPG Tarpit, the following message is displayed:

Server Error in '/epg-admin' Application.

The resource cannot be found.

CAUSE

EPG Web Management, prior to version 3.7.20, used ASP.NET SessionState of 'cookieless' which embeds the session token directly in the URL.  The August 2026 Windows Updates changed how .NET processes the URL-embedded session tokens, which causes the request to fail before the application can handle them. 

SOLUTIONS

Upgrade to EPG Web Management 3.7.20

-or-

Manually edit web.config under the following paths:

1. \Program Files\Messageware\EPG Web Management\WebAdmin
2. \Program Files\Messageware\EPG Web Management\WebReports
3. \Program Files\Messageware\EPG Web Management\WebTarpit

Change the following value:

<sessionState mode="InProc" cookieless="UseCookies" timeout="80" />

Save the file.