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Google Nest thermostats do not use jumper wires. Since your thermostats have jumper wires, do not connect them to your Nest thermostats. You may need to use a common wire or a Nest Power Connector to deliver constant power and stabilize the flow of current into the thermostat.
Please note to ensure that the power from your breakers to your heater is on and that both wires on your thermostat are seated firmly in their terminals (with no loose or exposed wires) to avoid power issues.
Have a look at this article and let us know if you need more help.
I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.