You need to use two hyphens. The flag is `-t` or `--trust`, not `–trust` so the following should work:


```bash
dotnet dev-certs https --trust
```

You can also run the help command to see more info

```bash
dotnet dev-certs https --help
```

[![dev-certs https help output][1]][1]



**See Also**: [How to run `dotnet dev-certs https --trust`?][2]



[1]: https://i.stack.imgur.com/zlr6u.png
[2]: https://stackoverflow.com/q/55485511/1366033

I have a problem with HTTPS when I am running (`dotnet run`) my .NetCore application locally on Windows.
It was working till my localhost certificate expired…

[![][1]][1]

I clean up old certificates and generated the new one by 

    dotnet dev-certs https –clean
    dotnet dev-certs https –trust

I’ve verified that everything was added to certmgr (Personal and Trusted certs), but I have the same problem.
It is keep trying to use old certificate which expired.
I do not know why it is trying to use old “localhost” certificate after clean up certs…

Do you have any idea what should I do?.

Thank you,
Błażej


  [1]: https://i.stack.imgur.com/A6cN6.jpg

How can I use new HTTPS localhost certificate

Answer