We are using the ORCID module in DSpace 9 in production since september. We noticed 2 kinds of errors (for specific references ; code 409 and 400, see examples below) when DSpace try to synchronize :
"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes""?>
<error xmlns=""
http://www.orcid.org/ns/error"">
<response-code>409</response-code>
<developer-message>409 Conflict: You have already added this activity (matched by external identifiers), please see element with put-code 192471604. If you are trying to edit the item, please use PUT instead of POST.</developer-message>
<user-message>There was an error when updating the record. Please try again. If the error persists, please contact CorpusUL for assistance.</user-message>
<error-code>9021</error-code>
<more-info>
https://members.orcid.org/api/resources/troubleshooting</more-info>
</error>
"
"<?xml version=""1.0"" encoding=""UTF-8"" standalone=""yes""?>
<error xmlns=""
http://www.orcid.org/ns/error"">
<response-code>400</response-code>
<developer-message>400 Bad Request: There is an issue with your data or the API endpoint. 405 Method Not Allowed: Endpoint and method mismatch. 415 Unsupported Media Type: data must be in XML or JSON format. Full validation error: HTTP 400 Bad Request (cvc-complex-type.2.4.a: Invalid content was found starting with element '{""
http://www.orcid.org/ns/common"":external-id-relationship}'. One of '{""
http://www.orcid.org/ns/common"":external-id-value}' is expected.)</developer-message>
<user-message>ORCID could not process the data, because they were invalid.</user-message>
<error-code>9001</error-code>
<more-info>
https://members.orcid.org/api/resources/troubleshooting</more-info>
</error>
"
I must say that those errors are exceptions, references are sent or updated without problems for the most part.
Thanks.