I have a Hair front loading HM-S800TVE (3100-5102-HMS80) washing machine. When I try to turn it on I get Err1. I had a power shortage yesterday that may have caused a problem? I opened the machine before it finished it's cycle which it did allow me to do. I also cleaned the filter that appeared to be clean but maybe I replaced it badly??

SOURCE: dripping wet clothes

will be an UNBalanced load, maybe there was not enough clothes in the load so in that case the drum would not be able to distribute the load evenly so gave up on the spin, hence wet stuff!

SOURCE: washing machine finished its last wash and is no longer working ?

All HAIER Washing Machines come with a 3 year parts and labour warranty - Ring them and get them to come and repair..

SOURCE: WASHING MACHINE DOOR WONT OPEN

Call the manufacture it will be under warranty if it's only 6 months old as the machine will have to be torn down to get to the defective switch, just the top will have to come off if your lucky.

SOURCE: My Haier waching machine has a slow spin cycle

I have the same problem with the same washer

SOURCE: my haier new washing machine

It sounds like the door lock has failed.
Call the seller before you do anything as you don't want to invalidate the warranty. You may be able to remove the top of the machine and defeat the interlock which is preventing the door opening from the inside.(REMOVE POWER FIRST)