99% of the time this is due to one of two reasons: 1) An increase in humidity causes the wood to swell, which makes the latch hard to press down. and 2) the string force just makes it hard to press down.
For a quick solution try grabbing the neck near the headstock with one hand and pressing the neck against the guitar body. With your other hand, use your THUMB to press down on the button. Pressing against the neck helps add a little distance between the latch pin and latch catch so it can disengage, and using your thumb gives you more force to depress the button.
If these don't work, you can reach out to us via the contact form for direct support. Less than 0.1% of the times is there a need to change a latch or do a major repair.