No Role found

Our client is receiving the error message "No Role found for signer email" when trying to send a package. We are creating a custom ID however the custom ID is guaranteed to be different (one ends in -1 the other in -2). only certain users are seeing this issue and are seeing it for every package they try to create. Our implementation is below.

Hi, i'm gettin this error message "OneSpanSign.Sdk.OssException: 'No Role found for signer email ", creating a package, this is the code that i'm using, thanks for the help.

 String API_KEY = "dzkxxxljQw==";
            String CLIENT_APP_ID = "17bbxxx338b";
            String CLIENT_APP_SECRET = "687964xxx79118c29";
            String BASE_API_URL = "https://sandbox.esignlive.com";    
            String API_URL = BASE_API_URL + "/api";