Remote syslog server configuration

Hi,

I have a UTM 9, and I am trying to send syslogs to my Splunk server. When I try to add the Splunk server information, specifically the DNS information, I get an error 

The hostname 'slc-p-splunk.xx.xxl' is already in use by the hostname list attribute of the host object 'Splunk'.

There are no other objects (see screenshot). How do I clear out this potentially old information?

Thanks!