Flat tire while sitting in the garage

Went in there to grab something and noticed the front tire was flat. I read that the sealant (Stan’s) needs to be done ever few months and warmer weather/storage will decrease the time in between so I’m hoping it’s just that. I pumped it up but it still bled out slowly (couldn’t hear anything.)

I have had poor luck with Stan’s. I’m going to give orange sealz a try. I have heard it is much better. I also tried using slime in addition to stans but it was no better.