{% if view.first_field_with_errors %}
The form field {{ view.first_field_with_errors }}
has errors,
but its error message is not being displayed, possibly because
you did not include the field in the page.
There are 2 ways to fix this:
formfield
tag, e.g.
{% templatetag openblock %}
formfield player.{{ view.first_field_with_errors }}
{% templatetag closeblock %}
formfield
but are instead
writing the raw HTML for the form input,
remember to include
{% templatetag openvariable %}
form.{{ view.first_field_with_errors }}.errors
{% templatetag closevariable %}
somewhere in your page's HTML.
The following other field(s) have the same issue:
{{ field_with_error }}
While debugging, you can display all errors in the form with
{% templatetag openvariable %}
form.errors
{% templatetag closevariable %}
.