Panasonic s550bf Door Latch

Bad luck. Are you sure you mounted everything everythinh exactly the way it was? No pieces missing or left over?
Best procedure is to that a photo of each step.
My adivec: Do it agaim carefulley. I no luck, look for a repair service
Maybe you can fine a video tutorial for your Microvwve in youtube?
Something like this
.
Broken microwave door
Samsung Microwave Door Latch Spring Repair when your door won latch closed
Over The Range Microwave Oven Door Repair Help
Repair Replace bad Door Switch Mechanisms on Whirlpool Microwave


and there are come more

Return itbto thecshop

see this causes and fix it. God bless you
Open Lever If the microwave door won't open the open lever might be broken. This part can be replaced separately.

Door Spring If the microwave door won't open the door spring may have broken. The door spring is located inside the door and keeps downward pressure on the door hook.

Door Latch If the microwave door won't open the door latch might be broken. The door latch is inside the microwave. The door hook, which is part of the door, engages with the latch to keep the door closed during operation. If the door latch or actuator breaks the door may not open.

Door Hook If the microwave door won't open the door hook might not be releasing properly. The door hook is installed inside the door and normally releases when the door is opened. The hook is made of plastic and will break over time. When this happens it will need to be replaced, it can't be repaired.

Button Spring If the microwave door won't open the button spring might be broken internally. The button spring can be replaced.
Button If the microwave door won't open the button might be broken internally. The button can be replaced.

Handle Actuator If the microwave door won't open the handle actuator might be broken. This is a plastic part which can become brittle over time. This part is connected between the door button and the door latch assembly.

it's a replaceable part. the upper and lower hooks are actually 1 part. door will need to be partially disassembled

sometimes things get stuck in the door latch mechanism causing the micro switch to jam..

I think you are quite right but it will have to be removed for service.
Disconnect the mains supply and place it on a sturdy covered table.
Remove the cabinet top/sides.
Check the door mechanism, you may find that one of the latches is not connecting properly and stops the other latch from lifting.
Spares are available from Panasonic dealers and espares.com etc etc etc.

try you local appliance dealer they could possibly order or repair it

In order to have the correct operation of the door latch mechanism and latch switches.

1. Ensure correct adjustment of the Door and the Latch switches.
2. Wipe off any dirt or grease around the door key where it touches the latch switched and door hooks with a soft cloth. Maintaining the smooth movement of the latch mechanism and switches etc�
3. After replacement of the latch mechanism and/or Latch switches. Make sure to confirm a smooth operation of these parts are in order.

to view the exact diagram of how to do this manually just click the link http://www.applianceaid.com/micro8.html

To replace the inner part of the latch is actually quite easy. Remove the glass tray from inside, then unplug the unit. Take to a flat surface and stand on edge so that the door will open flat. On the inside is a plastic trim that is just clipped on. Pop this off carefully and you will now see the assembly you need to replace. Note where the spring is anchored to the door before taking it apart. Put a small amount of lubricant on the guide pins of the new catch (petroleum jelly works great).

I have a semmins microwave working in great condition, last night the latch mechanism inside the microwave don't allow the door latch to close.Only the top portion, bottom portion is ok.