Hi there! I understand that your TempSpike was working but now won't connect to your iPhone. Let's work together to get that fixed.

First, to better assist you, could you please confirm a couple of things for me?
- Is your TempSpike probe currently inserted in the booster or separate from it?
- Have you tried closing the TempSpike app and restarting it on your iPhone?
- Is your iPhone's Bluetooth enabled and are other Bluetooth devices connecting normally?
- Are the TempSpike probe and booster fully charged?

Meanwhile, here's a safe checklist of steps to try that usually resolve connection issues:

1. Make sure both the TempSpike probe and booster are fully charged.
2. Remove the probe from the booster before trying to pair with the app, as the connection tests require the probe to be separate.
3. On your iPhone, go to Settings > Bluetooth and make sure Bluetooth is turned ON.
4. Close the TempSpike app completely (swipe it away from app switcher) and then reopen it.
5. Restart your iPhone to refresh connectivity.
6. In the TempSpike app, try to pair the probe again following the pairing instructions.
7. If available, try resetting the TempSpike booster by turning it off and on or pressing a reset button if applicable.

If this doesn't connect your TempSpike to your iPhone, please let me know exactly where you get stuck or if any error messages appear. We can then try a deeper troubleshooting method or check for any app or firmware updates.

You can also find an official support article here with similar advice: https://thermopro.zendesk.com/hc/en-us/articles/7287597532317-TempSpike-Pairing-Other-Issues

Let's nail this down step by step! How does it look so far with those checks?