It's always a 24 hour timer.
It sounds like you forgot to pick up your daily reward from earlier today, then when you picked it up, the timer switched over to the next reward.
The timers for me switch over at 7 p.m. my time (Central U.S. time). If I didn't pick up my reward yesterday, I could technically pick one up at 6:55 p.m. and then another five minutes later when it switched over at 7, but then the next reward after that wouldn't be until 7 p.m. again the following night.