We have identified an issue where the _PSU_1/PSU_2 support users does not work with B1UP.
If you try to start B1UP you will get the error:
The issue is that the DI-API gives the error: “10000004 – B1 License Error L_NO_SESSION”.
This error originates from the DI-API and prevents B1UP from connecting to the DI-API.
There is no workaround at this time. We are unable to connect to the DI-API and as a result, B1UP cannot run.
SAP intended to fix the issue in SAP Business One Client version 9.2 PL09 running with CCC PL08 or higher.
*** Update 2019
PSU users broke again afterward, the problem is described in this SAP Note: https://launchpad.support.sap.com/#/notes/2674581
It seems to be fixed (again) in SAP 9.3 PL06.