Please check the Fault bit in the configuration register. If it is set to 1, the Fault would be locked in once the overvoltage condition was sensed. A 1 needs to be sent to the Clear Fault status register in order to remove it.
MAX31856
Production
The MAX31856 performs cold-junction compensation and digitizes the signal from any type of thermocouple. The output data is formatted in degrees Celsius...
Datasheet
MAX31856 on Analog.com
Please check the Fault bit in the configuration register. If it is set to 1, the Fault would be locked in once the overvoltage condition was sensed. A 1 needs to be sent to the Clear Fault status register in order to remove it.