certificates generated by mkcert cause `mac verify failure`

[mwcz]

I'm attempting to use simple-http-server with mkcert to create valid certs for local development. I'm generating a P12 cert with mkcert, but simple-http-server rejects it with mac verify failure.

Here's a recording of the process:

https://asciinema.org/a/tFAgoaVnHB1j9OsdG4YiIZJvq

I'd guess this isn't simple-http-server's issue, just reporting it in case there's a known fix, or if anyone can point me to the library that's emitting the error (hyper?).