Error 502 when viewing billing page after trial ends
Received error when attempting to view Group Billing page of a GitLab.com account.
There are two errors occurring here:
1. Whenever a trial ends and a user goes to a group or personal billing page, a regression occurs
2. The group not found errors are also reported as part of this issue, and will be investigated separately
https://sentry.gitlab.net/gitlab/gitlabcom/issues/914258/
```
NoMethodError: undefined method `members' for nil:NilClass
admin/groups_controller.rb:19:in `show'
@group.members.order("access_level DESC").page(params[:members_page]))
action_controller/metal/basic_implicit_render.rb:6:in `send_action'
super.tap { default_render unless performed? }
abstract_controller/base.rb:194:in `process_action'
send_action(method_name, *args)
action_controller/metal/rendering.rb:30:in `process_action'
super
abstract_controller/callbacks.rb:42:in `block in process_action'
super
...
(117 additional frame(s) were not displayed)
NoMethodError: undefined method `members' for nil:NilClass
```
### Reports of same problem:
1. https://gitlab.zendesk.com/agent/tickets/132659
1. https://gitlab.zendesk.com/agent/tickets/130825
1. https://gitlab.zendesk.com/agent/tickets/131181
1. https://gitlab.zendesk.com/agent/tickets/131444
1. https://gitlab.com/gitlab-com/support/dotcom/dotcom-internal/issues/824
1. https://gitlab.zendesk.com/agent/tickets/131591
1. https://gitlab.zendesk.com/agent/tickets/134432
1. https://gitlab.zendesk.com/agent/tickets/134438
1. https://gitlab.zendesk.com/agent/tickets/136651
issue