To search the cause of a Gateway error an advanced log file must be created and send to the support.
Change following line in file Bentley.SelectServer.Gateway.exe.config
which is default located in C:\Program Files\Bentley\SELECTServer and can be opened e.g. with an editor <level value="INFO" /> in <level value="TRACE" />
Afterwards:
Now send file SS-Bentley.SelectServer.Gateway.exe.log and other available log files in folder ...\program files\bentley\Selectserver\logs zipped to Bentley
https://www.bentley.com/en/support
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