Shibboleth SP3 Problem: xmltooling::IOException setHeader (Header) failed: -2147024809

[Rod Widdowson]

 > Then there really isn't any doubt, nor any doubt that IIS is so broken that it apparently doesn't honor the setting you're trying to
> change, or has some inherent limitation that overrides the setting.

I have the very vaguest of memories that IIS can get a bit upset if you try to set a header which has some sort of sematic meaning (and in particular REMOTE_USER rings bells).  Are there any names like that?

If you add a case to JIRA so I don't forget, it would not be hard to add better logging in the future.

As for debugging it - I am assuming that this is a production machine?  If so then I have no ideas.

If it was in a test environment and if (in particular) you were happy with using the tools I'd suggest attaching a debugger to IIS [1].  But that’s because I'm a developer and if all you have is a hammer everything looks like a nail.

[1] https://wiki.shibboleth.net/confluence/display/SP3/RemoteDebugWindows