Guy's Behavior

Why would he suddenly take forever to reply?

There's a guy I met online and we started texting daily, he was the one who started the conversation tbh, after about a week or more of texting he asked to facetime to get to know each other better and I agreed. (He lives abroad so it was difficult to meet) Anyways, we talked for a bit and he said he liked my vibes and that we should facetime more often. He even told me that he re downloaded snapchat and that we can move our conversation there and we kept on texting daily until one day he just replied after 2 days (and he continued the convo as if nth happened, he didn't say any excuse for why he was late) and he asked me a question about myself and I replied after an hour and asked him another question (since we're still getting to know one another) and another 2 days had passed still with no reply.
Why would he suddenly take forever to reply?
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