Hi Meagan,
It appears you're encountering issues updating fields in your ThingSpeak channel. To perform updates, you must use the Write API Key specific to your channel.
Based on the "entry 0" information, it seems there's a possibility you might be using the Read API Key instead. Double-check the API key you're currently using within your setup. Ensure that it is indeed the Write API Key associated with your ThingSpeak channel. After verifying and switching to the correct API key if necessary, attempt to update the field again. If the problem persists and you continue to experience the same issue, reach out for further assistance.
For more information on ThingSpeak you can refer below:
Hope it helps!