Hi Zoƫ
Don't use glue.
The connection needs to conduct electricity and glue is not the best conductor.
Does that round connection fit on the spade connection that is at the end of the wire shown ?
If so - you could try using a pair of pliers to squash it a little to make it tighter ( be careful here ) or ......
you could use a little kitchen ( aluminium ) foil between the joint so that the joint is tighter.
Is this a possibility ?