3422923 - Username and Password authentication fails after ENGINEAPI upgrade - "Invalid LogonID received"

After updating the SAP NetWeaver Java ENGINEAPI component to SP28 or higher, basic/form-based (username + password) login fails for some users (e.g. "Administrator").

In the Security Troubleshooting Wizard (TSHW) the following error messages may be seen: "Invalid LogonID received. LOGONID_TOO_LONG" or "SPEC_CHAR_REQU" or "LOGONID_TOO_SHORT"

SAP NetWeaver Application Server for Java

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