For Nagios XI is usual web access URL http://some.domain:port/nagiosxi
In that case, For Nagios Core access URL is http://some.domain:port/nagios and that address should be used in Nagios API URL configuration field.To check if the URL is correct, try in the web browser access is usual web access URL http://some.domain:port/nagios/cgi-bin/objectjson.cgi?query=hostgrouplist
some.domain and port should be replaced by actual values from your installation.
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