HTTP Error 500.19 Solution

[a_cutler2]

In a customer's environment today App Broker went down and in the web browser a 500.19 Internal Server Error was showing (details in the screenshot). Based on the information shown in the browser, it looked like there was a  problem with duplicates in the web.config file, specifically line 284 was causing a problem. Just trying different things to try and fix it I ended up commenting out that line, saving the web.config file and accessing App Broker again - it worked. However, I'm sure that this method isn't the best way of addressing this issue and I'm wondering if anybody can shed some light on what's actually going on here, and what risks I might be running by commenting out that line and still running App Broker.

[CharlesW]

I'd guess that something had changed at a higher level (at the default web site).. Perhaps somebody made a modification, which conflicted with the App Broker web.config. On Googling the error a number of individuals have suggested adding a remove statement prior to the add to avoid the conflict, rather than simply commenting out the add. For instance:

<remove name="Strict-Transport-Security" />

<add name="Strict-Transport-Security" value="max-age=31536000; includeSubDomains" />