I have updated my Cerbo GX to version 3.01 and have no temperature sensor connected. Since the update my solar controller did not charge anything anymore. After a lot of searching I found that the low temperature cut off was enabled and that the Cerbo was giving me now -1 celsius, which is lower than 5 degrees. When I disabled the low cut-off thing started working like normal again. I have no need for a temperature sensor in my system since have those on my BMS and Inverter/charger.
I do not know what the output was before but must have been higher than the 5 degrees Celsius since have not changed anything except the update of the Cerbo.