Chrome 58+ drops support for CN in SSL certs, which means (at least on my machine) that browsing sites hosted in IIS Express throw constant security warnings.
How do I change my IIS Express SSL certificate for one that will work with Chrom 58+?
The answer Chris gave solves the issue, thanks! Because my whole team had this issue, I created a little Powershell script to run the steps in Chris' answer.
https://gist.github.com/camieleggermont/5b2971a96e80a658863106b21c479988
Running this in elevated mode did the trick for me.