Logon Groups Refreshing Problem

Hi all

We have a problem on our webas 640.

- I create a Logon Group (SMLG) name Z_SEB on the central instace

- After that I check on the message server the entries in SMLG. The entry done on the central instance does not appear

- When I create it on the instance server I get a short dump, because the value is already in the database.

Is this behaviour normal or do we have a communication problem beetwen message and instance server?

Thanks in advance

Serge