I am writing a view which is accepting a email as parameter passed by url like
url(r\'^admin/detail_consultant_service/((?P\\[A-Z0-9._%+-]+
If you have more than one application in a project, which is most likely the case here, your url should be namespaced. The url in the template should be in this format as explained Here
{% url 'My-App-Name:my-url-name' args or kwargs %}
Hence your code shoul look like this,
{% url 'Your-app-Name:consultant_service_detail' consultant_id=consultant.id %}