After upgrading my Test system to SBM v12.1, not only I cannot access the workcenter with HTTP 403 error, but also I saw lots of warnings in the ns.log file stating that "Unable to send event xxxxxxx of the notification xxx because of: java.lang.IllegalArgumentException: Username cannot be empty."

I found this knowledge base D27994 https://knowledgebase.serena.com/InfoCenter/index?page=content&id=D27994&token=ae08aaf524db45c5bfd9d7528c06610b with a recommended workaround. However I don't know how to do the first step by "creating a system user inside SBM which has permissions to attach files to the items." Since I cannot access the workcenter yet, so I really don't even know how to create just a regular user without using the SBM Admin Portal.

Please help!