My boyfriend has been ignoring me.

I'm a 23-year-old woman in a relationship with a 23-year-old man, and we've been together for two years. Lately, he has been ghosting me for 3-4 days at a time—no calls or messages, just a "good morning" text. This happens even after we've had good conversations, and then he just stops responding. When I bring it up, he says he wasn't in the mood or thought I might be busy, which seems odd since he has nothing to say for days. Recently, he mentioned binge-watching a series and managed to finish eight seasons—around 80 episodes—in just three days, yet he can't find the time to message me. I’m at a loss for what to do. Any advice?