I have a similar problem that is frustrating. I can manually run zones, but as soon as my schedule starts, it shows 'Offline' but the schedule does seem to run. I get notifications when the schedule is delayed due to rain or other factors, but as soon as it's scheduled, the app shows the device offline (but I can ping it and it shows active in my router) and it doesn't catalog the event. Shows the last time it ran was 4/13, but it did go this morning. I have done everything listed in the troubleshooting steps but to no avail. It began happening after 4/13 but before the latest iOS app update. I have a Gen 1 device and within 30 feet of my router.
Below is a screen of the last two manual device power cycles when the schedule was supposed to run. Device was working nominally and then went offline when the schedule was supposed to run. It appears that the zones were watered, but was not captured, and I had to power cycle device to have it show online in the app and web. No scheduled times ran between these two due to current rain and climate conditions that forced them to be skipped as advertised.