Neither updates nor apps installing “unable to install” … “please try again later”

Hi,

issue is on both my iPhone and my iPad - I cannot install the iOS18 update and I cannot update or install new apps. When installing apps it says “unable to install” … “please try again later”, after it actually started and you saw the progress circle going to 20% or so.

Tried restarting applications and devices. Tried on iPhone and iPad, tried signing out and back in from app store with Apple ID.