WHat happens when you turn on the machine? The first thing is the door locks. This is often by a heater and bimetal actuator (means the door stays locked for a while even if power goes off - makes certain the drum has stopped if it was spinning at the time)
Yours may be taking a while to engage. Possibly that's how it was meant to be, possibly it is deteriorating.
If you had told us the make and model maybne we could have done some more research (like YOU should have done anyway) and been a bit more forthcoming.
Anon, May 2016