PVC glue is not like a traditional glue where it just bonds the pipes together.
When you apply PVC glue to PVC pipe it creates a chemical reaction between the PVC material and the glue which then bonds it together.
When you use PVC glue you should put the plumbing fittings together quickly and twist it back and forth a few times and hold it for at least 1 minute.
Then allow the PVC cement to cure for at least 2 hours before you turn on the water to avoid it bursting off.
It's said that you can turn the water back on within 15 minutes but the last time I tried that the fittings came apart so I started waiting the 2 hours which is the full cure time for the PVC and never had any problems.