We are unable save setting in CF Admin using the ColdFusion(2018) administrator window

Store the following code as a CFM page and launch it in the browser. If all goes as expected, it will open the ColdFusion Administrator page.

<!---Rotate the session and log in to Coldfusion Administrator. --->
<cfset sessionRotate()>
<cfset  createObject("component","cfide.adminapi.administrator").login("Your_CFAdmin_Password")>
 
<!--- Redirect to the ColdFusion Administrator page --->
<cflocation url="http://127.0.0.1:8500/CFIDE/administrator/index.cfm">

Now, log in.

Clear your cookies for the site (localhost or whatever it is). You may have a duplicate cfid or cftoken cookie.

If you have reason not to want to, you can prove if this is the issue by changing the domain to an ip, or vice-versa (so localhost to 127.0.0.1).

Or you could try your admin from a different browser. 

Let us know how it goes.