Updating all users usernames Using REST API - Jira Data Center

[Reab]

Hi, 

I would like to update all Jira users' usernames using bulk update through rest API. 

this documentation didn't work for us : https://confluence.atlassian.com/jirakb/how-to-bulk-update-users-email-addresses-in-jira-using-rest-api-948218723.html 

We keep getting 403 Error  with bulk update :  Basic Authentication Failure - Reason : AUTHENTICATION_DENIED 

and with single update Jira logs shows a severe error:  com.sun.jersey.spi.container.ContainerRequest.getEntity A message body reader for Java class com.atlassian.jira.rest.v2.issue.UserWriteBean, and Java type class com.atlassian.jira.rest.v2.issue.UserWriteBean, and MIME media type application/octet-stream was not found. The registered message body readers compatible with the MIME media type

However, I can Issue a GET request put not a PUT request.

How can I Update all users usernames using REST API 

Thanks

[Kurt Klinner]

@Reab 

Can you share the script/call that you use to test the modification?

Cheers

Kurt