Even though Kepler-423b is as black as charcoal, the planet’s dayside would still appear utterly glaring. The extreme closeness to its host star means that the insolation the planet receives is a few hundred times more intense than what Earth receives from the Sun. Reflecting just a few percent of that intense insolation would still create nothing short of a blazing glare. Temperatures on the planet’s dayside can get as high as ~2000K.
Gandolfi et al. (2015), “Kepler-423b: a half-Jupiter mass planet transiting a very old solar-like star”, arXiv:1409.8245 [astro-ph.EP]