Error while installing requirements.yml file: reg

[Manu Kumar]

Greetings...

                   Hi team,

                                 I am facing issue while installing the openwisp2 from my laptop. I am getting an error like, I have attached in the mail. Please let me know asap how to overcome this and the error is from the requirements file.  So the content of the requirements.yml file is :

---
roles:
- src: https://github.com/<mygithubaccount>/ansible-openwisp2.git
version: master
name: openwisp.openwisp2-dev

collections:
- name: community.general
version: ">=3.6.0"

[Manukumar NM]

am able to solve this error: now am encountering new problem: 

TASK [Stouts.postfix : Install requirements (Debian)] ******************************************************************************************************************************************************
[DEPRECATION WARNING]: Invoking "apt" only once while using a loop via squash_actions is deprecated. Instead of using a loop to supply multiple items and specifying `name: "{{item}}"`, please use `name:
['postfix', 'ca-certificates', 'mailutils', 'libsasl2-modules']` and remove the loop. This feature will be removed in version 2.11. Deprecation warnings can be disabled by setting
deprecation_warnings=False in ansible.cfg.
failed: [-----------------] (item=[u'postfix', u'ca-certificates', u'mailutils', u'libsasl2-modules']) => {"ansible_loop_var": "item", "changed": false, "item": ["postfix", "ca-certificates", "mailutils", "libsasl2-modules"], "msg": "Failed to update apt cache: "}

PLAY RECAP *************************************************************************************************************************************************************************************************
               : ok=2    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0   

I ran : sudo apt-get update manually. I don't see any error while executing that command.