The Pokemon Company has announced that the Pokemon HOME service is set to undergo maintenance on Wednesday 22nd September at 1am UTC to 6am UTC on the Nintendo Switch system and iOS and Android devices. Therefore you won’t be able to access the application on either Switch or mobile during the 5 hours that the service will be down for. Once maintenance has finished, a new update will become available for the smartphone app which will bring it to Version 1.5.
Pokemon HOME server maintenance announced

I guess they are getting it ready for Brilliant Diamond and Shining Pearl.
My Greninja and Camerupt are still on ultra moon. I need a proper switch game where I can use them because they can’t be transferred to shield. I got my quiet Camerupt from omega ruby. They get surf, thief, ice beam, grass knot, flame thrower, earthquake, hyper beam and stone edge.