I often have this problem - with some weed killer yesterday.
Have a container of liquid with a trigger you keep pulling to spray the contents.
On my experience. If it works at all it works for a while, then the trigger has no effect. If you keep tryong eventually it may start working again. Then the process repeats.
Is there a trick to getting these to work as one would assume, or is it just me and my product choices? Getting so I'm considering trying to only buy gas powered sprays with the button on the top or not at all.
TIA