Could be many things, for example:

- the wallet is not the right type or is not defined

- you have more than one wallet installed or the there's no default wallet defined by iOS

https://nostr.build/av/nostr.build_3eebdf2b383d6ae24caa1f10d55d60b4feaf8faf5584b38b736db0b63eaa7ac1.mov