Versions:
---------
- 17.0
Steps to reproduce:
-------------------
1. Install any custom module.
Issue:
------
Odoo raises the error "Connection to %s failed; the module %s cannot be
downloaded."
Cause:
------
The "activate" button on custom modules triggers the "button_immediate_install_app"
method instead of "button_immediate_install" because the "module_type" field is
empty for custom modules.
Solution:
---------
Display the "button_immediate_install" button on the modules kanban view when
the "module_type" is empty.
closesodoo/odoo#141744
Signed-off-by: Pierre Masereel (pim) <pim@odoo.com>