In lcpserver/api/license.go, an error returned from completeLicense() should not always be expressed as err 500. In our case, if the key is not found, a 404 ("Content not found") is expected.
Note that this error type is not found in problem.go, I guess it must be added.
If a normal error type exists (http 404 not found), we don't need to add an extra type. I'll just return the 404 / Not Found error code. (see also https://tools.ietf.org/html/rfc7807#section-4)
In lcpserver/api/license.go, an error returned from completeLicense() should not always be expressed as err 500. In our case, if the key is not found, a 404 ("Content not found") is expected. Note that this error type is not found in problem.go, I guess it must be added.