Hi, i try to join Chapter but not succeed, while submitting showing this error

Uncaught Server Exception
Traceback (most recent call last):
File “/home/frappe/benches/bench-2017-01-23/apps/frappe/frappe/website/render.py”, line 45, in render
data = render_page_by_language(path)
File “/home/frappe/benches/bench-2017-01-23/apps/frappe/frappe/website/render.py”, line 139, in render_page_by_language
return render_page(path)
File “/home/frappe/benches/bench-2017-01-23/apps/frappe/frappe/website/render.py”, line 155, in render_page
return build(path)
File “/home/frappe/benches/bench-2017-01-23/apps/frappe/frappe/website/render.py”, line 162, in build
return build_page(path)
File “/home/frappe/benches/bench-2017-01-23/apps/frappe/frappe/website/render.py”, line 181, in build_page
html = frappe.render_template(context.source, context)
File “/home/frappe/benches/bench-2017-01-23/apps/frappe/frappe/utils/jinja.py”, line 69, in render_template
return get_jenv().from_string(template).render(context)
File “/home/frappe/benches/bench-2017-01-23/env/lib/python2.7/site-packages/jinja2/environment.py”, line 1008, in render
return self.environment.handle_exception(exc_info, True)
File “/home/frappe/benches/bench-2017-01-23/env/lib/python2.7/site-packages/jinja2/environment.py”, line 780, in handle_exception
reraise(exc_type, exc_value, tb)
File “”, line 1, in top-level template code
File “/home/frappe/benches/bench-2017-01-23/apps/frappe_theme/frappe_theme/./templates/web.html”, line 1, in top-level template code
{% extends base_template_path %}
File “/home/frappe/benches/bench-2017-01-23/apps/frappe_theme/frappe_theme/./templates/base.html”, line 43, in top-level template code
{% block content %}
File “/home/frappe/benches/bench-2017-01-23/apps/frappe_theme/frappe_theme/./templates/web.html”, line 70, in block “content”
{{ main_content() }}
File “/home/frappe/benches/bench-2017-01-23/apps/frappe_theme/frappe_theme/./templates/web.html”, line 40, in template
{%- block page_content -%}{%- endblock -%}
File “”, line 19, in block “page_content”
File “/home/frappe/benches/bench-2017-01-23/env/lib/python2.7/site-packages/jinja2/environment.py”, line 430, in getattr
return getattr(obj, attribute)
UndefinedError: ‘chapter’ is undefined

Thank you so much for reporting this netmanthan!

Your error report can be found here https://github.com/erpnext/foundation/issues/231

And Welcome to ERPNext!