After reading the raw HTML of the attached horizon-bug.html,
I confirmed ext_net_dict is an empty dict {}.
There are the following possibilities:
(a) Admin user fails to retrieve external network lists
(b) Neutron returns an empty list.
(c) Horizon calls Neutron API with wrong user.
Perhaps it is a bug of not Horizon but Neutron itself, but I am sure with 100%.
If you are using devstack, the detail of Neutron API calls are logged to /var/log/apache2/horizon_error.log.
Please let us know if you can still produce this error.
After reading the raw HTML of the attached horizon-bug.html,
I confirmed ext_net_dict is an empty dict {}.
There are the following possibilities:
(a) Admin user fails to retrieve external network lists
(b) Neutron returns an empty list.
(c) Horizon calls Neutron API with wrong user.
Perhaps it is a bug of not Horizon but Neutron itself, but I am sure with 100%.
If you are using devstack, the detail of Neutron API calls are logged to /var/log/ apache2/ horizon_ error.log.
Please let us know if you can still produce this error.