Hello @Ozgur
I have checked some details on a test Org I have and seems like the GET Alerts for a Template is returning "
{"type":"clientConnectivity","enabled":false,"alertDestinations":{"emails":[],"snmp":false,"allAdmins":false,"httpServerIds":[]}" but when I tried to push the same values returned by the GET through a PUT to the same Template, I got the same clientConnectivity error.
I think you should open a support case so that we can investigate with our developers and get back to you with this one.
Let me know if you have any questions.
Regards,
Meraki Team