1. Personal emotions or stress: He may be facing personal stress, work troubles, or low mood, which temporarily prevents him from communicating with others, including you.
2. Communication issues or misunderstandings: Something may have happened before that made him feel misunderstood or communication was not smooth, so he chose to temporarily keep his distance.
3. Dynamic changes in relationships: The level of intimacy and interaction in a relationship may change over time, and he may be reevaluating your relationship status or requiring some personal space to think.