Please try to avoid posting screenshots and quote your code instead, as this makes it much easier to help you. Also try to make sure, you provide a complete working example, as you didn’t define multiplyHPsi anywhere. This thread may be helpful to you:
That said, does your code work on a previous version of Julia? What version of LinearMaps.jl are you using? (You can find that out with ]st LinearMaps in the REPL.)