Exchange 2016: Fix ASP .NET error, Event ID 1309

Sometimes in Exchange 2016 or 2019, you have a server that hums with no errors and then you get those that give you a little more grief. You way have come across a warning for ASP.NET for the path C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\rest that gives an error for "maxQueryString Length value", below is the error:

https://www.collaborationpro.com/wp-content/uploads/2020/12/image-2.png

The fix is not too difficult in this case to fix. You need to navigate to the path listed above which is:

• C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\rest

First make a copy of the web.config file as we need to edit it. Open up Notepad elevated and navigate to the path above. Once open scroll down till you see <httpRuntime maxRequestLength.......

https://www.collaborationpro.com/wp-content/uploads/2020/12/image-3-1024x143.png

We need to add in the line highlighted above, the output will look like this:

https://www.collaborationpro.com/wp-content/uploads/2020/12/image-4-1024x143.png

I didn't restart the transport service but left it and this event cleared.