HTTP403 Error caused by server update: August 11, 2020-KB4569746 Cumulative Update for .NET Framework 4.8 for Windows 10 version 1607 and Windows Server 2016

Question

When the update 2020-08 was installed on our Windows 2016 server we were unable to access a system on the server for a number of days. We encountered the HTTP403 error whenever we tried to access the system. Once we reset the server to a state prior to the update the access to the system was back. I'm wondering if this was a common problem with this update? What element of the update would have caused the HTTP403 error?

Note: We are not 100% sure whether it was the 2020-08 update, it may have been a previous version. Nevertheless, any info on what could cause a HTTP403 error from these types of errors would be greatly appreciated. Also, access to the system is granted through Okta Authentication. Would this have caused an issue?

Thanks in advance.

Answer 1

@Cathal (ext) Hi Cathal,

Thank you for your reply.

After discussed with IIS engineer, we think your issue is more related with IIS, so we recommend to create a new thread on IIS forum. They have more resources for you.

Microsoft IIS forum:
https://forums.iis.net/

Bests,

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Answer 2

Analyze the HTTP error logs in C:\Windows\System32\LogFiles\HTTPERR.

What about the system eventlog and the IIS logs themselves? What errors do you find in them?

Install the updates on a test machine first to verify functionality before you update production servers and impact end users.