The most common reasons for this are: 

1. At your altitude, the boiling point of water is lower than 100ºC (212ºF). For where to check it or how to change it, see here.
2. At 98ºC (208.4ºF), is it a rolling boil? If so, please change your boiling temperature point on the App. For where to check it or how to change it, see here.
3. The thermometer probe on the controller is not pushed all the way into the thermowell.
4. The thermometer is loose in the thermowell, add a small amount of food-grade thermal paste to the probe to get a firm fit.
5. If it is none of these, wait until you see visible boiling, then using the app, skip to the boil stage which will start the timer and allow for the continuation of the brew day. Contact us for further troubleshooting.