Hey @KDM Thanks for letting us know!
Does your iMac have a hard-wired connection to the router or are you connecting using WiFi? If you’re using WiFI, please connect your Core directly to the router - do you still experience this issue?
Is there any change if you reboot the Core?
Does this happen for all endpoints or only some?
It might also be helpful to have a complete description of your setup using this link as a guide.
Thank you! 