NoLifeKing

You could always check the Event Viewer for warnings/errors from ASP.NET. :)

This is how my backend (with modifications) looks for the stats, with working admin-tools to `DRAIN`, `MAINT` and `READY` backends and servers. ```plaintext backend app ... snip snip ... acl...

Getting the same issue with version 4.0.5, in .NET 4.8 Framework website/apps

Exception with `Object Reference`-error ```plain System.NullReferenceException: Object reference not set to an instance of an object. at System.Net.Http.Headers.HttpHeaders.ReadStoreValues[T](Span`1 values, Object storeValue, HttpHeaderParser parser, Int32& currentIndex) at System.Net.Http.Headers.HttpHeaders.GetStoreValuesAsStringOrStringArray(HeaderDescriptor descriptor, Object sourceValues,...

And then the `Index out of range` ```plain System.IndexOutOfRangeException: Index was outside the bounds of the array. at System.Net.Http.Headers.HttpHeaders.ReadStoreValues[T](Span`1 values, Object storeValue, HttpHeaderParser parser, Int32& currentIndex) at System.Net.Http.Headers.HttpHeaders.GetStoreValuesAsStringOrStringArray(HeaderDescriptor descriptor, Object...

I'll see if I can make a small repo solution.

After applying `.ConfigureAwait(false)` to all awaited calls, it is still happening. Will try to reproduce this in a small reproduction repository during the day.

Can't reproduce in a small repo (localhost), will try to deploy it internally and see if it reproduces

@ebozduman Here's a repo that reproduces when deployed behind HAProxy. So my guess is that something in our HAProxy does something strange. https://github.com/MultinetInteractiveOSS/MinioHeaderRepro

The repo needs a few environment variables to be set (to get a Minio instance working, with a specific file) I'm currently home sick, so I don't have the HAProxy...