As long as this is a guy who has been promptly replying to your text messages, until this isolated incident, you should still give this guy the time of day.
Even though he left you on read for over 24 hours, don’t read too much into it.
This isn’t an indication that he doesn’t care about his relationship with you.
Something came up during that time that made him unable to reply to your message in a timely fashion.
Consider what is currently going on in his life.