Hi Yoha
Thanks for your post, welcome to the Community Forums.
Sorry to hear you currently have a red light on your Hub. For the Hub 3, this can indicate that the Hub is potentially overheating but please don't worry, we can help.
Firstly, can you please ensure that the Hub is sat upright, in a clear and well ventilated area. Secondly, please also perform a factory reset on the Hub to ensure that all the settings are as they should be. Please note, however that in doing so, any customisations made to the settings will revert back to default. To do this, you'll need to push a pin into the pinhole of the Hub for at least 60 seconds.
Once you've done all of the above and if you still have a red light, please let us know and we can arrange a home engineer visit for you.