Update DOI Registration exception message; (DOECODE-544)

Author: sowerstl

src/main/java/gov/osti/services/Metadata.java

@@ -1558,7 +1558,7 @@ private Response doSubmit(String json, InputStream file, FormDataContentDisposit
                     // tell why the DataCite registration failed
                     log.warn("DataCite ERROR: " + e.getMessage());
                     return ErrorResponse
-                            .internalServerError("DOI registration failed. Please try again later.")
+                            .internalServerError("The DOI registration service is currently unavailable, please try to submit your record later. If the issue persists, please contact [email protected].")
                             .build();
                 }
             }
@@ -1754,7 +1754,7 @@ private Response doAnnounce(String json, InputStream file, FormDataContentDispos
                     // if DataCite registration failed, say why
                     log.warn("DataCite ERROR: " + e.getMessage());
                     return ErrorResponse
-                            .internalServerError("DOI registration failed. Please try again later.")
+                            .internalServerError("The DOI registration service is currently unavailable, please try to submit your record later. If the issue persists, please contact [email protected].")
                             .build();
                 }
             }