[BUG] "IMyInterface doesn't look like a Refit interface"after upgrade from 4.6.58 to 4.8.14 (or 5.1.67)

Describe the bug

I have a very simple interface with one method that worked just fine in version 4.6.58. After I did upgrade to 4.8.14 (tried with latest 5.1.67 as well) and clean rebuild with no cached packages I get this error:

IOAuthClient doesn’t look like a Refit interface. Make sure it has at least one method with a Refit HTTP method attribute and Refit is installed in the project.

Steps To Reproduce

This is my interface:

using System.Threading.Tasks;
using Refit;

public interface IOAuthClient
{
    [Post("/oauth/token")]
    Task<TokenResponse> GetToken([Body] TokenRequest request);
}

and register it like this:

RestService.For<IOAuthClient>(oauthHttpClient) // Error happens at this line

Expected behavior

No errors in the newest version of the library.

Screenshots

Environment

• OS: Windows
• Device: Desktop
• Version: 10
• Working Version: 10

Additional context

I use .Net Framework 4.7.2 in my Project. I have another .net core project that uses a newer version of the library and there are no troubles there. Perhaps it’s framework version related