FB Messenger on iPad

I am trying to install FB Messenger on my second (my daughter doesn't want it) iPad. It is a 6th generation iPad (for some reason I cannot find that in the device selection below) with 128GB (96GB free). It is updated to iPadOS 16.1 and all the other apps are working fine. FB Messenger just gives me a black/grey screen with a white progress circle in the middle. I have installed it, removed it, turned the iPad off/on, reinstalled...all of this multiple times. I deleted it straight from the Home Screen and from from within settings. Does anyone know anything that may be causing this problem? Messenger works fine for me on my iPad Pro, iPhone and MacBook Pro.