You’re getting this error because of the localhost url that you have specified in your routing policy.
I’m pretty sure there’s an extended setting to deactivate this behavior, but the easiest way to bypass the error would be to use your computer name instead of localhost. You could also add a entry in your /etc/hosts with a domain name that points to your localhost, and use this domain name at routing level.
Another option would be to use an alias in your routing url.
#webMethods#API-Management#API-Gateway