Error on self.call_service()

Third party integrations AppDaemon
1

Hey! I am trying to set back the temperature of a thermostat after 2 hours. I do this by calling on the service evohome/set_zone_override. Getting an error every time I try this. Could anyone please help?
Here is my code:

import hassapi as hass
class tempback(hass.Hass):
    def initialize(self):
        global climate
        climate=self.args['climate']
        climate = str(climate)
        self.listen_state(self.getstate,"input_boolean.turnscript")
        self.listen_state(self.getstate, climate, attribute='temperature')

    def getstate(self, entity, attribute, old, new, kwargs):
        temp = self.get_state(climate, attribute="status")['setpoint_status']
        if temp['setpoint_mode'] == 'TemporaryOverride':
            self.set_state("input_text.text1", state=True)
            self.call_service('evohome/set_zone_override', entity_id="climate.tiebe", setpoint=15, duration='{"minutes": 5}')
        else:
            exit(0)

And this is the error:

2020-03-28 14:53:30.826540 WARNING HASS: Code: 400, error: 400: Bad Request```