This problem is known defect "LVWB-1898 Alerts interface not working in Streaming 10.6" which affects LiveView Web 1.6.0. It is expected to be fixed in LiveView Web 1.6.1 or later.
The workaround is to open the LiveView Web alerts configuration page directly in your browser using URL:
http://host:10080/lv/monitor/#/manager Replace "
host:10080" with the hostname (or IP address) and service port number matching the Server URL provided in the TIBCO Spotfire Data Streams NEW CONNECTION dialog:
The direct Manage Alert Rules page looks like this:
Changes made here take immediate effect.