Gives an error when trying to run the playbook a second time. Ansible + F5 BIG-IP

Trying to add a user to an F5 bigip with Ansible and also trying to change the default password (admin) to a new password specified in the admin_passwd variable.

This is my config:

The first time I run the playbook the result is successful:

But when I try to run it a second time (having deleted the user from the first run), I get the following error.

Why is this happening and how can I correct it?

Thanks in advance