Filtered deck with multiple tags

Hi, all my cards have tags to indicate their subject matter and some of them have another tag to indicate a key term. I want to build a filtered deck which shows cards which are a certain subject as well as being a key term. I have tried various things including tag:internet+tag:key1 in the search field. I thought I read somewhere this would work, but it says no cards match the search. They do match, and they are not suspended and I don’t have any other filtered decks. Is someone able to help me please?
thank you.

Searching for tag:internet tag:key1 should work.

[When multiple search terms are provided, Anki looks for notes that match all of the terms - an implicit ‘and’ is inserted between each term.
Searching - Anki Manual