System.ArgumentOutOfRangeException: Length cannot be less than zero. Parameter name: length

[Charles]

Ok, I think we have found the cause of this issue.

In this post you recommended putting “Ignore” in the Request.Items to ignore any incoming bearer tokens.

Remove authorization header

You shouldn’t attempt to mutate incoming Request Headers which should be considered immutable. Instead logout the user before sending an Authentication request otherwise it considers the same Authenticated User is authenticating with an alternative sign in option. You can “override” the Authorization Header by specifying a non empty (i.e. null || “”) in the IRequest.Items dictionary, e.g: httpReq.Items[Keywords.Authorization] = "Ignore"; If it doesn’t start with a "Basic " or "Bearer " pref…

This caused the issue when trying to do the Substring(0,-1) here:

My workaround was to use httpReq.Items[Keywords.Authorization] = “Ignore Ignore” but I think this fix should be on your side so that setting to a simple “Ignore” works as you expected it to.