Ansible include_vars: Including dictionary variables from a file

"Doesn't work" is a very vague description of your problem, but this is not a valid task definition:

  - name: Dict test
    include_vars: test1.yml
    debug:
      msg: "User {{ item.key }} is {{ item.value.name }} ({{ item.value.telephone }})"
    loop: "{{ lookup('dict', users) }}"

include_vars and debug are individual actions so they need to be separate tasks; as you have it this should give you the helpful error ERROR! conflicting action statements: include_vars, debug

  - include_vars: test1.yml

  - name: Dict test
    debug:
      msg: "User {{ item.key }} is {{ item.value.name }} ({{ item.value.telephone }})"
    loop: "{{ users | dict2items }}"