Failed to Authenticate HTTPS connection when attempting GET from WebAPI

The most straight forward solution I found for this problem was to remove the cert and add it with the trust flag.

dotnet dev-certs https --clean
dotnet dev-certs https --trust

PS. I know this is old but I am just going to leave this here for someone that might stumble to this issue.

I had the same problem. After many hours of checking everything possible and even some impossible stuff, I managed to trace it back to wrongly generated SSL certificate.

I was creating mine according to this manual: How to: Create Your Own Test Certificate.

The certificate is generated using this command:

makecert -sv yourprivatekeyfile.pvk -n "cert name" yourcertfile.cer -r

where if -r is omitted, described error occurs.

Then pfx must be generated according to the manual. If one uses just cer, Kestrel will not start successfully.

I solved it by generating a new SSL certificate.