WinCC 7.4 SP1 Update 9: IE and WinCCRTViewer works locally, but not from a client

I have the same problem.

WinCC 7.4 SP1 update 9. There is no way for the webnavigator to work. IE and WinCCRTViewer works locally, but not from a client. I have tried everything. The IIS works since from the client it connects to the Server IP and you can install the packages, but then it says that there is no connection with the server when it tries to connect. I have modified the registry even for the ICMP ping problem topic. I have been installing this solution for many years and I don't know what the problem is now.

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Split from WebNavigator client stop working remotely after update.