GEONIS server mask cannot be opened, "Culture is not supported."

Question

Why can't I open a GEONIS server mask when I use a custom language?

Problem

GEONIS server mask cannot be opened, in the logs there is the following message: "Culture is not supported. Parameter name: name cu is an invalid culture identifier."

Solution

You should check if you have registered the appropriate CU culture. The language must be registered on the server where ArcGIS Server is running. This can be created using the GEONIS Culture Tool.

https://resources.geocom.ch/documentation/protected/others/2018/application/GEONIS_server/2017_1/DE/webhelp/index.html?gns_cu_culture_registrieren.htm