Probably just a delay. Give it a couple of days. Worse is when tracking shows delivered and it never arrived. You wonder if your neighbors got it by mistake and then boom, it shows up.

Happened a few times before, always got it the next day I wouldn't worry too much

Mail carriers are not what they used to be. Many are deliberately only visiting a handful of neighborhoods each day while stockpiling the rest of the mail to deliver several days worth on whatever day they get to each respective neighborhood. Some scan all the mail as delivered each day, some let the system go into "late mode," which seems is what happened to you. They work 3 hours a day getting paid for 8, but they feel it's justified because everyone still gets their mail eventually.

In any case, a day or two is too soon too really stress. If you havent gotten it by the end of the week, maybe do some spring cleaning

I've had this happen a few times. It always came the next day.

However, pretty recently, I had one say out for delivery and then "delivered / individual picked up at post office" -- that one never came.. no idea o_O