Server rule could not be set up due to an error

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My environment:
em Client v10.3.1567, Windows 11 EDU, Grommunio 2.45.0 via EWS

I tried to create a server rule with em client. When saving the rule, I get this error:

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grafik737×296 7.83 KB

Furthermore, I cannot retrieve server-based rules with the client.
There are no problems using Outlook (Office16).

EM Client or Grommunio error?

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