Download Cisco RTMT Real Time Monitoring Tool via direct URL

Perhaps your browser doesn't allow you to download Cisco RTMT from your CUCM | Application | Plugins link.  I suspect this might be a standard setting in more security conscious locations.

Try this: https://your_CUCM_url_or_IP_address:8443/plugins/CcmServRtmtPlugin.exe

Now when you get it installed and it is visually unusable, check this bug out:  https://quickview.cloudapps.cisco.com/quickview/bug/CSCva07316

1. Right click your RTMT executable
2. Click Compatibility tab
3. Click Change High DPI Settings button
4. Check Override high DPI scaling behavior.
5. Choose System from dropdown

Enjoy your Cisco RTMT.