Help my bathroom cupboard wont open

[Nikkiaddis]

In our Rapido 2003 motorhome we have a small mirror cupboard in the bathroom .
It will not open

Usually you press left middle on mirror and it releases and opens mirrored door

We have used it previously but it now won't open

Any ideas ?

 

[Parksy]

Try pressing the edge of the mirror quickly using a sort of flicking action.